I use the wafers as test objects to verify my eddy-current measurement setup. As they have a well-defined thickness and homogeneous conductivity, they are ideal for my application.
150mm Silicon Wafers all Diameters and Specifications
When were 150mm Silicon Wafers Introduced?
Introduced in 1983, 150mm (5.9 inch, usually referred to as ("6 inch") are either undoped, boron doped, phosphorous doped, arsenic doped, antimony doped and can have low or high-doping. Orientation can be (100), (111), (110). 150mm wafers can use the CZ or FZ method for ingot growth. 150mm silicon can also be thinned to 25 micron if required. One or two flats are also available.
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150mm Silicon Wafer Growth is Strong
This is impressive growth, supported by a slowly growing variety of applications such as the manufacture of "More Moore's Devices." As long as we continue with the class of equipment mentioned here, it is clear that the future of 150 mm wafer technology is bright.
Mechanical Grade Silicon Wafers Used in Neurobiological Research
Researchers from the Tata Institute of Fundamental Research in India are using our 150mm, mechanical grade, SSP silicon wafers in their work on Simple Microfluidic Devices. These devices are used for live cell imaging. The followng wafer was used for this research.
Si Item #478 - 150mm Mech Grade Si 650um SSP MECH
150mm Silicon for Testing of Wafer Handling Equipment
The following wafers wafers used by a major Solar OEM to test their wafer handling equipment.
Silicon Item: 857 - 150mm P /B <100> 0-10 620um SSP
150mm Silicon to Check the Surface Quality of Wafers in the Process of Production of Devices
Companies have used the following si wafer spec for production of test station to check the surface quality of wafers in the process of production of devices.
Item# 3465 - 150mm P-type Boron doped <100> 1-100 ohm-cm 625um SSP Test Grade
150mm Silicon Wafers Used in ESC for DRIE Tool
Researchers have used the following 150mm silicon substrate that are perfectly round, without flats and fit into their DRIE tool.
Si Item #3269
150mm P/B <100> 1-20 ohm-cnm 1000um SSP Prime Grade
Silicon Wafers Used to Analyze Surface Contamination
A scientist asked:
We are not looking for specific characteristics as thickness, diameter, doping, orientation, and so on. We just need to really know if the Test Grade is clean enough to work immediately as received, so that we can use the wafer surface to collect contamination and then analyze it. For this first trial we need just 25 wafers.
UniversityWafer, Inc. Quoted and Sold the Following:
Si Item #857
6", 675um, SSP, P/B<100>, 1-10 ohm-cm, Prime Grade
150mm Silicon Wafer Market Trends
As the business continues to undergo a number of changes, chip manufacturers will need to keep an eye on the silicon wafer industry, according to a new report from Cree Inc., which estimates that chip manufacturers "demand for 150mm wafers will approach $2 million. First, Cree's estimate is approaching $1 million for a 150mm wafer by 2023, based on an impressive CAGR of 110% from 2017 to 2026 and an even higher growth rate in the second half of the decade. Overall, demand for silicone wafer surfaces is forecast to grow by 1.5% annually until reaching 2.2 million in 2020, a significant increase over the current annual growth rate. Global shipments of silicon wafers increased faster than in the same period in 2016 compared to the first quarter of 2017. [Sources: 7, 8]
This huge growth is being seen in a device industry that is in its infancy and is limited to a wafer size of 150mm, but there are a number of hurdles that the market needs to overcome to increase sales. [Sources: 1, 7]
In a 2012 interview published in Semiconductor Engineering, lithographer Chris Mack explained that a 450 mm wafer would only reduce the cost of the die of a 300 mm wafer by 10 to 20 percent. In 2012, he claimed that only 10 to 20% had reduced the cost of matrices compared to 300 mm wafers, which are lithography-related. [Sources: 3, 4]
The conversion to a larger 450 mm wafer would reduce the price of the die by 10 to 20 percent, although the costs here are related to the number of wafers and not to their area. The cost of a silicon silon wafer with a diameter of 150 mm (or even 300 mm) has increased in recent years due to its size. [Sources: 3]
A study by Transparency Market Research expects the global silicon wafer market to continue on a steady path of registering a CAGR of 6.8% over the forecast period of 2017 to 2025. Indeed, the company says demand could lag behind demand from next year and remain tight until 2021. Silicon wafer suppliers have said the average selling price will be about $1,500 per square foot for 150 mm, allowing investment in a 300 mm extension. [Sources: 1, 8]
This is impressive growth, supported by a slowly growing variety of applications such as the manufacture of "More Moore's Devices." As long as we continue with the class of equipment mentioned here, it is clear that the future of 150 mm wafer technology is bright. [Sources: 7]
If you need more background on the language of this article, it was originally published in the October / November 2014 issue of the International Journal of Solid State Circuits. [Sources: 4]
F Furnace - Grade Test Wafers are a type of silicon wafer that differs from an ordinary silicon wafer in that it is not strictly related to the SEMI - M1 - 0302 protocol, but has also had a significant influence on the development of the current state - the art of solid state circuits. [Sources: 0, 6]
However, it complies with the surface metal level normally specified by the IC industry and the requirements of the SEMI protocol - M1 - 0302, such as thickness, width and thickness. [Sources: 5]
The Czochralski process is a method of growing high-purity crystals from semiconductors such as silicon and germanium. The high resistance of silicon is produced with a crucible that is not used for crystal growth, and the silicon crystals contain 5x1022 atoms per cm3. Other elements known as doping agents are often added, melted and melted to molten silicon, but the degenerated semiconductor is still no more than 99.9999% silicon. In comparison, the resistance of the other two most common silicon materials, gallium and cobalt, is around 32% and 66% respectively. Under sterile conditions, silicon melts to about 1.5% of its original state, or about 0.1%. [Sources: 2, 4, 7]
The iPhone X uses the 150mm GaAs substrate to produce RFFE RF components with the VCSEL facial recognition photodetector. Gallium can also be used as a semiconductor material for use in high-performance electronics such as cameras. P-type wafers can be doped with boron, which is the same as the p-structure, where the epi-wafer layer is of a different type. [Sources: 2, 5, 7]
Mechanical grade silicon wafers can be used for process development applications that are not sensitive to particles and surface defects. Manufacturers of semiconductor capital equipment also use process tests of silicon wafers to develop and characterize semiconductor manufacturing processes. By using silicon test wafers as automation hardware, the system manufacturer simulates the process of production and end customers with the silicon wafer. [Sources: 6]
In terms of equipment, the silicon wafer market is divided into two categories: device and consumer level. This figure is the total size of the global silicon wafer market in volume and value. [Sources: 1, 7]
Prime wafers are the highest possible quality silicon wafers, but different Prime wafers are used. There are three additional classifications of premium wafers designed for special process applications. [Sources: 2, 6]
Sources:
[1]: https://www.transparencymarketresearch.com/silicon-wafers-market.html
[2]: https://cleanroom.byu.edu/ew_wafer_specs
[3]: https://en.wikipedia.org/wiki/Wafer_(electronics)
[5]: https://www.sciencedirect.com/topics/engineering/silicon-wafer
[7]: https://www.appliedmaterials.com/en-in/node/3361906
[8]: https://semiengineering.com/silicon-wafers-ma-and-price-hikes/
Silicon Used for Eddy-Current Measurements
A corporate scientist requested the following:
Si Item #1575
100mm P/B <100> 0.01-0.02 ohm-cm 525um SSP Prime
Rerference #ONL5710 for specs and pricing.
How are Silicon Substrates Used for Eddy-Current Measurements?
Eddy current testing is a nondestructive testing method widely used to examine materials for defects, measure thickness of materials, and inspect conductivity. It's based on the principles of electromagnetic induction.
In this technique, an alternating current is passed through a coil, creating an alternating magnetic field. When this coil is brought close to a conductive material, such as a silicon substrate, it induces eddy currents in the material. The flow of these eddy currents then creates a secondary magnetic field that opposes the initial field. Any change in the material's properties - such as a crack, inclusion, or a change in thickness or conductivity - will alter the eddy current and, therefore, the secondary magnetic field. By measuring these changes, one can infer the presence of defects or other features.
Now, in the context of silicon substrates:
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Thickness Measurement: One of the primary uses of eddy current measurements on silicon substrates is to measure their thickness. By analyzing the changes in the eddy current signal, one can infer the thickness of the substrate. This can be particularly useful in applications where the silicon wafer thickness must be tightly controlled.
-
Material Defect Analysis: Eddy current testing can also be used to identify defects within the silicon substrate, such as cracks, voids, or inclusions. These defects can alter the eddy current flow, which can be detected and analyzed.
-
Doping Level and Type Determination: The conductivity of a silicon substrate can be affected by its doping level and type (n-type or p-type), both of which can influence the eddy currents. As such, some researchers and manufacturers use eddy current measurements as a non-destructive way to determine the doping characteristics of a silicon substrate.
However, it's important to note that silicon is a semi-conductive material and its conductivity is much lower than that of metals. Therefore, the eddy currents induced in silicon are not as strong as those in metals, and the measurements are not as straightforward. Nonetheless, with proper calibration and understanding of the properties of silicon, eddy current techniques can be successfully applied.
150mm (6 Inch) Silicon Wafer Inventory
We have a large selection of 150mm Si wafers in stock and ready to ship. Please fill out the form if you need other specs and quantity. Below is just a small sample of what is in stock.
| Item | Dia | Type | Dopant | Orien | Res Ω | Thick (um) | Polish | Grade | Description |
|---|---|---|---|---|---|---|---|---|---|
| 478 | 150mm | N/A | 650um | SSP | MECH | Low cost Si Wafer great for spin coating. | |||
| 857 | 150mm | P | B | <100> | 0-10 | 620 um | SSP | Test | Test Grade Silicon great for wafer processing studies. |
| 1025 | 150mm | N | <100> | 0-100 | 625um | SSP | Test | 6" diameter (150mm), silicon wafers, N-type. | |
| 2880 | 150mm | P | B | <100> | 0.006-0.012 | 525um | SSP | Test | With Oxide Back Seal |
| 3071 | 150mm | P | B | <100> | 1-100 | 500um | SSP | Test | 2 SEMI-STD FLATS WHERE THE PRIMARY FLAT IS <110> |
| 3175 | 150mm | P | B | <111> | 0-0.003 | 525um | SSP | Test | No Certificate available, wafers sold "As-Is". |
| Item | Material | Orient. | Dia (mm) | Thck(μm) | Polish | Res Ω | Comment |
| 1383 | Undoped | [100] | 6" | 650um | SSP | FZ >10,000 ohm-cm | |
| 2476 | N/P | [100] | 6" | 675um | SSP | FZ 2,000-10,000ohm-cm | Prime Grade, Float Zone (FZ) |
| 857 | P/B | [100] | 6" | 625um | P/E | 0-100 ohm-cm | Test Grade with flat |
| 478 | TYPE-ANY | ANY | 6" | 625um | P/E | Resistivity-ANY | Mech Grade with flat |
| 2312 | P/B | [100] | 6" | 675um | P/E | 0.01-0.02 ohm-cm | With EPI layer, Hard wetblast/LTO L.M. |
| 2305 | P/B | [100] | 6" | 725um | P/E | 14-22 ohm-cm | sd-soft laser mark |
| 2306 | P/B | [100] | 6" | 635-715um | P/E | 10-30 ohm-cm | 1 semi std. flat |
| 2307 | P/B | [100] | 6" | 650-700um | P/E | 10-30 ohm-cm | 2 semi std flats |
| 2308 | P/B | [100] | 6" | 610-640um | P/E | 0.008-0.02 ohm-cm | WITH EPI layer, poly bagged & labeled silicon wafers |
| 2309 | P/B | [100] | 6" | 650-690um | P/E | 100-200 ohm-cm | |
| 2310 | N/P | [100] | 6" | 625um | P/E | 56-72.5 ohm-cm | Poly-SI |
| 2311 | P/B | [100] | 6" | 675um | P/E | 15-25 ohm-cm | Poly-SI L.M. |
| UW1972 | N/Phos | [100] | 6" | 320um | P/E | 2000-8000 ohm-cm | Prime Grade, Float Zone (FZ) |
| E869 | P/B | [100] | 6" | 675 | P/P | FZ 10,000-20,000 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| 5869 | P/B | [100] | 6" | 675 | P/P | FZ 5,000-20,000 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| 6123 | P/B | [100] | 6" | 350 | P/P | FZ 2,700-3,250 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| G503 | P/B | [100] | 6" | 900 | C/C | FZ >50 | SEMI Prime, 1Flat, MCC Lifetime>6,000μs, Empak cst |
| E239 | n-type Si:P | [100] | 6" | 825 | C/C | FZ 7,000-8,000 {7,025-7,856} | SEMI, 1Flat, Lifetime=7,562μs, in Open Empak cst |
| E700 | n-type Si:P | [100-6° towards[111]] ±0.5° | 6" | 675 | P/P | FZ >3,500 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| F700 | n-type Si:P | [100-6° towards[111]] ±0.5° | 6" | 790 ±10 | C/C | FZ >3,500 | SEMI, 1Flat, Empak cst |
| 4982 | n-type Si:P | [100-6° towards[111]] ±0.5° | 6" | 675 | P/P | FZ >1,000 | SEMI Prime, Notch on <010> {not on <011>}, Laser Mark, Empak cst |
| D982 | n-type Si:P | [100-6° towards[111]] ±0.5° | 6" | 675 | BROKEN | FZ >1,000 | SEMI notch Test, Empak cst, Broken into many large pieces. One piece ~50% of wafers other pieces ~20% of wafer |
| 5325 | n-type Si:P | [100] | 6" | 725 | P/P | FZ 50-70 {57-62} | SEMI Prime, 1Flat (57.5mm), Lifetime=15,799μs, Empak cst |
| E325 | n-type Si:P | [100] | 6" | 725 | P/P | FZ 50-70 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| N445 | n-type Si:P | [112-5.0° towards[11-1]] ±0.5° | 6" | 875 ±10 | E/E | FZ >3,000 | SEMI, 1Flat (47.5mm), TTV<4μm, Surface Chips |
| G343 | n-type Si:P | [112-5° towards[11-1]] ±0.5° | 6" | 1,000 ±10 | C/C | FZ >3,000 | SEMI, 1 JEIDA Flat (47.5mm), Empak cst, TTV<4μm, Lifetime>1,000μs |
| 5822 | Intrinsic Si:- | [100] | 6" | 575 | P/P | FZ >10,000 | SEMI Prime, 1Flat (57.5mm), MCC Lifetime>1,200µs, Empak cst |
| 6178 | Intrinsic Si:- | [100] | 6" | 675 | P/P | FZ >10,000 | SEMI notch Prime, Empak cst |
| E179 | Intrinsic Si:- | [111] ±0.5° | 6" | 750 | E/E | FZ >10,000 | SEMI notch, TEST (defects, cannot be polished out), Empak cst |
| G458 | P/B | [110] ±0.5° | 6" | 390 ±10 | C/C | >10 | Prime, 2Flats, Empak cst |
| 3882 | P/B | [100] | 6" | 675 | P/E | 50-150 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| 6287 | P/B | [100] | 6" | 675 | P/E | 5-10 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| 5929 | P/B | [100] | 6" | 400 | P/P | 1-30 | SEMI Prime, 1Flat (57.5mm), Empak cst, TTV<5μm |
| 5686 | P/B | [100] | 6" | 415 ±15 | P/P | 1-30 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| 5354 | P/B | [100-9.7° towards[001]] ±0.1° | 6" | 525 | P/P | 1-100 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| S5838 | P/B | [100] ±1° | 6" | 575 | P/P | 1-20 | SEMI Prime, 1Flat (57.5mm), Empak cst, TTV<2μm |
| O698 | P/B | [100] | 6" | 675 | P/P | 1-100 | SEMI Test, Both sides dirty and scratched, 1Flat, Empak cst |
| 5421 | P/B | [100] | 6" | 675 | P/E | 1-10 {4.5-6.5} | SEMI notch Prime, Empak cst, TTV<7μm |
| N698 | P/B | [100] | 6" | 675 | P/E | 1-100 | SEMI Prime, 1Flat, Empak cst |
| 5733 | P/B | [100] | 6" | 750 ±10 | E/E | 1-5 | SEMI, 1Flat, Soft cst |
| 6049 | P/B | [100] | 6" | 2,000 | P/P | 1-35 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| 6096 | P/B | [100] | 6" | 400 ±15 | P/P | 0.5-1.0 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| S5834 | P/B | [100] | 6" | 365 ±10 | E/E | 0.01-0.02 | SEMI Prime, 1Flat (57.5mm), TTV<2μm, Empak cst |
| F770 | P/B | [100-6° towards[111]] ±0.5° | 6" | 675 | P/P | 0.01-0.02 | SEMI Prime, 1Flat (57.5mm), Empak cst, Both sides with scratches |
| E770 | P/B | [100-6° towards[111]] ±0.5° | 6" | 675 | P/E | 0.01-0.02 | SEMI Prime, 1Flat (57.5mm), Empak cst, Both sides polished but only front is Prime |
| Y206 | P/B | [100] | 6" | 675 | P/E | 0.01-0.02 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| 6005 | P/B | [100] | 6" | 320 | P/E | 0.001-0.030 | JEIDA Prime, Empak cst |
| D005 | P/B | [100] | 6" | 320 | P/E | 0.001-0.030 | JEIDA Prime, Empak cst |
| 6237 | P/B | [100] | 6" | 675 | P/P | 0.001-0.005 | SEMI, 1Flat (57.5mm), Empak cst |
| 9023 | P/B | [111-4.0°] ±0.5° | 6" | 625 | P/E | 4-15 {7.1-8.8} | SEMI Prime, 1 JEIDA Flat(47.5mm), Empak cst |
| I324 | n-type Si:P | [100] | 6" | 725 | P/P | 5-35 | SEMI Prime, 1 JEIDA Flat(47.5mm), TTV<2μm, TIR<1μm, Bow<10μm, Warp<20μm, With Laser Mark, Empak cst |
| 5814 | n-type Si:P | [100] | 6" | 925 ±15 | E/E | 5-35 | JEIDA Prime, Empak cst, TTV<5μm |
| 5728 | n-type Si:P | [100] | 6" | 675 | P/E | 2.7-4.0 | SEMI Prime, in Empak cassettes of 24 wafers |
| B728 | n-type Si:P | [100] | 6" | 675 | P/E | 2.7-4.0 | SEMI Prime, in Empak cassettes of 6 & 7 wafers |
| S5837 | n-type Si:P | [100] | 6" | 250 ±5 | P/P | 1-3 | SEMI Prime, 1Flat (57.5mm), TTV<2μm, Empak cst |
| S5644 | n-type Si:P | [100-4° towards[110]] ±0.5° | 6" | 675 | P/E | 1-25 | SEMI Prime, 1Flat(57.5mm), Empak cst |
| S5913 | n-type Si:P | [100] ±1° | 6" | 800 | P/E | 1-10 | SEMI Prime, 1Flat(57.5mm), Empak cst |
| F859 | n-type Si:P | [100-25° towards[110]] ±1° | 6" | 800 | C/C | 1-100 | SEMI notch Prime, Empak cst |
| E089 | n-type Si:P | [100] | 6" | 1,910 ±10 | P/P | 1-100 | SEMI Prime, 1Flat (57.5mm), Individual cst, TTV<2μm |
| F089 | n-type Si:P | [100] | 6" | 1,910 ±10 | P/P | 1-100 | SEMI Prime, 1Flat (57.5mm), Individual cst, TTV<5μm |
| H727 | n-type Si:P | [100] | 6" | 3,000 | P/P | 1-100 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| M176 | n-type Si:P | [100] | 6" | 5,000 | P/P | 1-25 | Prime, NO Flats, Individual cst |
| 5252 | n-type Si:Sb | [100-6° towards[110]] ±0.5° | 6" | 675 | P/P | 0.01-0.02 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| C673 | n-type Si:Sb | [100] | 6" | 675 | P/E | 0.008-0.020 | SEMI Prime, 1Flat (57.5mm), Empak cst |
| 2533 | n-type Si:As | [100] | 6" | 1,000 | L/L | 0.0033-0.0037 | SEMI, 1Flat(57.5mm), in individual wafer cassettes |
| E533 | n-type Si:As | [100] | 6" | 1,000 | L/L | 0.0033-0.0037 | SEMI, 1Flat(57.5mm), in individual wafer cassettes |
| 4204 | n-type Si:As | [100] | 6" | 675 | P/EOx | 0.001-0.005 | SEMI Prime, 1Flat (57.5mm), Empak cst, backside LTO 0.6um, TTV<3μm, Bow/Warp<15μm |
| 5541 | n-type Si:P | [100] | 6" | 675 | P/EOx | 0.001-0.002 | SEMI Prime, 1Flat (57.5mm), with strippable Epi layer Si:P (0.32-0.46)Ohmcm, 3.20±0.16μm thick, Empak cst |
| D339 | n-type Si:P | [111] ±0.5° | 6" | 675 | P/E | 1-100 | SEMI Prime, NO Flats, Empak cst |
| 1660 | n-type Si:As | [100] | 6" | 675 | OxP/EOx | 0.001-0.005 | SEMI TEST (spots & minor visual defects), 1Flat (57.5mm), Thermal Oxide 0.1μm±5% thick, Empak cst |
| H503 | P/B | [100] | 6" | 735 | P/P | FZ >50 | Prime, 1Flat, Empak cst, TTV<2μm |
| K343 | n-type Si:P | [112-5° towards[11-1]] ±0.5° | 6" | 800 ±10 | P/P | FZ >3,000 | SEMI, 1 JEIDA Flat (47.5mm), Empak cst, TTV<4μm, Lifetime>1,000μs |
| L343 | n-type Si:P | [112-5° towards[11-1]] ±0.5° | 6" | 950 ±10 | P/P | FZ >3,000 | SEMI, 1 JEIDA Flat (47.5mm), Empak cst, TTV<4μm, Lifetime>1,000μs |
| H178 | Intrinsic Si:- | [100] | 6" | 675 | P/P | FZ >10,000 | SEMI notch Prime, Empak cst |
| G264 | P/B | [100] | 6" | 675 | P/P | 1-5 | SEMI Prime, 1Flat, Soft cst |
150mm Silicon Wafer Dopants Available
Boron Doped Silicon Wafers
150mm (6") Antimony Doped Silicon Wafers
150mm (6") Arsenic Doped Silicon Wafers
150mm (6") Undoped Silicon Wafers
150mm (6") Gallium Doped Silicon Wafers
Industrial Temperature Sensors
We have the Silicon Wafers for industrial temperature sensors applications. Below is what clients have chosen for their research.
| 150mm P/B (100) >20,000 ohm-cm 300um SSP Prime Grade |
150mm N/Ph (100) 1-5 ohm-cm 500um SSP Prime |
150mm P/B (100) 1-15 ohm-cm 350um SSP Prime Grade |
|---|
Please contact us for pricing.
What Wafers are Used in Millimeter-Wave Photoconductive Switches?
A univeristy scientists needed help sourcing the correct wafer for their research.
"Our application is millimeter-wave photoconductive switches. We need really low loss silicon for one state, and long carrier lifetime for the other."
UniversityWafer, Inc. Quoted reference #266464 for pricing.
150mm Undoped high resistivity silicon >1000 ohm*cm wafers DSP around 500um thick
Applications of Millimeter Wave Photoconductive Switches
This article will introduce you to the basic concepts of High-speed photoconductive switches and their applications. You will also learn about typical configurations and measurements. Finally, you will learn how to design your own millimeter wave photoconductive switch. If you are interested in learning more, read on! Here are some examples of applications for millimeter wave photoconductive switches. The applications are almost endless! Here are just a few:
High-speed Photoconductive Switches
A new generation of high-speed photoconductive switches is allowing us to operate at much higher frequencies than photodiodes. This is possible because they exploit the high electrical conductivity of ultrafast incident light. Researchers have demonstrated the operation of high-speed millimeter wave photoconductive switches in an on-wafer environment. The NIST scientists have also developed chip-scale on-wafer pulse generators that will allow us to calibrate connectorless electronics in the future. In addition to demonstrating on-wafer photoconductive switches, they have demonstrated high-speed circuits in the terahertz regime.
The key to high-speed millimeter wave photoconductive switches is the generation of jitter-free, ultra-fast electrical pulses. The authors report that the generation of these pulses can be achieved by integrating solid multilayer transparent dielectrics into the photoconductive switch's construction. They demonstrate that a high-speed millimeter wave photoconductive switch can be implemented in a high-speed pulse-train generator, high-speed optical pulse detector, and wide-band analog sampler.
High-speed millimeter wave photoconductive switching has become a reality thanks to recent breakthroughs. The research team led by W.L. Cao, Y.Q. Liu, and S.N. Mao reported on a novel technique to develop a high-speed millimeter-wave photoconductive switch. The team worked closely with E.E. Funk, R.W. Waynaant, and Marwood Ediger to develop this technology.
However, the use of terahertz technology remains limited by the lack of convenient sources and detectors. While this technology is still in its early stages, hybrid systems combining photonic devices are helping to improve their specifications and stabilities. There are a number of ways in which these hybrid systems can be used. This article briefly explores one such technology. And, as always, we encourage further research into this new technology!
Typical Configurations
A submillimeter wave generating integrated circuit comprises a network of N photoconductive switches biased across a common voltage source. Each switch has a different optical delay from the common optical pulse, which is applied to successive switches with a corresponding delay. The switches are spaced apart by a suitable switch-to-switch spacing. Typical configurations of millimeter wave photoconductive switches comprise N switches, each of which generates a submillimeter wave frequency, f, on the order of Nf0.
The array of Auston switches is aligned in a parallel fashion across the voltage source and the output load. The submillimeter wave output is transferred through a microstrip circuit. A laser beam illuminating the back side of the integrated circuit substrate enables the switches to be aligned along a wedge-shaped refractive layer. This wedge-shaped layer narrows in thickness along the direction of the switches, and the spacing D between two adjacent switches is corresponding to a delay time of 1/f.
An alternative embodiment of the present invention comprises a plurality of linear switch arrays formed on an integrated circuit. These switch arrays form a submillimeter wave line radiator and will have a higher power output than an RF antenna. In addition, they can be effectively integrated with cylindrical quasi-optics. While a typical configuration of millimeter wave photoconductive switches consists of a capacitor plate with a characteristic inductance L, the antenna 200 will have a characteristic inductance L.
In addition to their spectral range, a photoconductive switch can be configured to produce a narrowband or broadband output. The S-parameters of such a device determine its switching efficiency. In addition to the switching efficiency, a photoconductive switch's average output power is limited by its average photoelectric conversion efficiency. For this reason, a recent switch design is able to generate millwatt-scale average power into free space.
The top conductor of a microstrip waveguide consists of a semi-transparent top conductor. A voltage source applied between the top conductor 148 and the ground plane 151 produces a photoconductive signal. In addition, when the sweeping laser illumination 150 is incident on the top conductor, it penetrates the semiconductor substrate. Thus, a photoconductive switch is produced.
Measurements
The current study demonstrates how millimeter-wave photoconductive switches function in the presence of a bias. A bias is a voltage that induces a change in the photocurrent. In this experiment, a nanosecond pulse laser diode (SPL PL90-3) was used. Its wavelength is 905 nm, its rise time is 7.1 ns, and its single pulse energy is 1.6 mJ. The SPL PL90-3 has a rectangular shape and a trigger spot area of 8.31 mm2 in the center of the two electrodes.
A recent paper published in the journal Optics Letters reported that an optically controlled coplanar waveguide switch can operate at frequencies up to 382 GHz. A multilayer model was used to simulate photoinduced plasmas, and measurements of optical mixing at a frequency of 212 GHz showed good agreement between measured and simulated results. These findings also revealed that this switch requires as little as 175 mW of optical power at a wavelength of 980 nm and can eliminate bandwidth.
Researchers at the University of Maryland and the Massachusetts Institute of Technology reported that a vanadium-nitrogen doped 4H-SiC photoconductive switch exhibited high power and low jitter. However, the researchers did note that the output waveforms exhibited very low noise levels. As a result, the device's output waveforms were stable and their power output was highly predictable.
Power measurements in submillimeter waves require cryogenic detectors with low noise levels. One such device developed by NIST/Boulder has measured noise-equivalent powers of nine pW, which was the world record until recently. This result was achieved by the high-Tc transition edge bolometer. In addition, measurements in the submillimeter region are difficult to verify accuracy due to the presence of unknown harmonic content, spurious oscillations, and contaminating lines.
The challenge is to produce a device that can measure 10 mW and has a time constant of less than ten seconds. This could be achieved with a prototype device based on a WR-10 waveguide input. This prototype device has a 100-k/W responsivity and a time constant of seven seconds. The root mean square drift is seven mW, and the device's sensitivity could be improved by improving the insulation. The work could be further advanced by the involvement of NIST.
Applications
High-speed, high-bandwidth communications signals are advancing at a rapid pace. To ensure accuracy, waveform measurement instruments must utilize highly calibrated photodiodes to generate well-characterized calibration signals. Current photodiodes' bandwidth is limited by two factors: switching speed in semiconductor technologies, and frequency limit of coaxial interconnects. However, NIST researchers have developed solutions to both issues.
The key component of a photoconductive switch is its photoconductivity, which increases when exposed to light. By irradiating the material, the light absorbed by the semiconductor generates free carriers. These free carriers contribute to the conductivity. Various semiconductor materials can be used in photoconductive switches, including low-temperature-grown gallium arsenide, chromium-doped gallium arsenide, indium phosphide, and silicon on sapphire. The lifetime of these photoexcited carriers determines the recovery time of the switch.
The invention of these millimeter-wave photoconductive switches was patented by several scientists. Chi H. Lee and P.-T. Ho, as well as R.W. Waynaant and Marwood Ediger, have published papers in a variety of journals. In addition to these, the authors of a number of conference papers have patented photoresistive superconductor switches.
Moreover, MEMS switches have gained tremendous research interest. The key advantage of these photoconductive switches is that they do not require bias lines or swathing mechanisms. The main radiator of a radio-frequency antenna can be reconfigured mechanically, and no bias lines or complex systems are needed to modify the antenna. The device can operate at a high frequency without generating harmonics and intermodulation distortion.
Video: Photoconductive Research Explained
Microreactor Array Device
Researchers from University of Arizona used the following 150mm Silicon Wafers for their Microreactor Array Device research: UniversityWafer, Inc. 150mm 675um+/-25um. Electrical properties and crystal orientation of the silicon do not matter. Polished side of the wafer coated with 300nm of LPCVD low stress Nitride.
Microarray Terms
- microarray scanner
- fluorescent microarray
- microreactor arrays
- microkinetic model
- microtiter plate
- micropillar arrays
- process parameters
- transformational devices
- membrane tests
- reactor development
- protein microarrays
- individual microreactors
- scanner image
- experimental data
- #permeable membrane
What is a Microreactor Array Device?
Microreactor array device is a platform that can be used to conduct several chemical reactions simultaneously under identical operating and chemical conditions. The physical principles behind the design of such a device are explained in the following paragraphs. The operation of microreactor arrays includes filling each with a reagent, displacing any excess, and sealing each. In a typical process, a microreactor array may be used to produce a single, multiple-component protein.
