Low Stress Nitride on Silicon Wafers

university wafer substrates

Low Stress Nitride Silicon Wafers

A researcher asked for the following quote:

What substrate do I need for making silicon nitride membrane
with KOH etch? Would you be able to provide me a sample wafer of 100nm thick silicon nitride? We are not too happy with our current supplier and we want to make sure the new supplier would be able to provide similar quality of nitride for membrane fabrication.

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UniversityWafer, Inc. Quoted:

This is for Low Stress LPCVD Nitride <250 MPa tensile. Film thickness uniformity is +/- 5% depending on incoming quality of substrates. If test wafers it is +/- 10%. Would need to know window size in order to know if Low Stress is fine or if they need a Targeted film stress.

Reference #205975 for specs and pricing.

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What are 5 Applications of Low Stress Silicon Nitride?

Researchers have used our low stress silicon nitride substrates for a variety of research applications inlcuding the following:

  1. Microelectromechanical systems (MEMS) - Low stress nitride deposited on substrate is used to fabricate micro-electromechanical systems such as accelerometers, pressure sensors, and resonators.

  2. Optoelectronic devices - Low stress nitride deposited on substrate is used as a protective layer for optoelectronic devices such as light emitting diodes (LEDs), solar cells, and laser diodes.

  3. Microfluidics - Low stress nitride deposited on substrate is used as a surface coating for microfluidic devices to reduce wear and tear and improve the stability of the devices.

  4. Data storage devices - Low stress nitride deposited on substrate is used as a protective layer for magnetic and optical data storage devices such as hard disk drives and CD/DVDs.

  5. Biosensors - Low stress nitride deposited on substrate is used as a surface coating for biosensors to improve the stability and accuracy of the sensors and prevent bio-fouling.

What Low Stress Nitride Spec are Needed For TEM Grids for Graphene Liquid Cell Project?

A postdoctoral researcher requested the following quote:

I was wondering if you produce any low stress silicon nitride on thin wafers? I swear, I saw 100mm wafer with 200um thickness in the nitride section a few days ago, but I can’t find it in your catalogue. We basically need a 100mm wafer, 200~250um thick with DSP of 150nm of nitride.

We were planning to make custom TEM grids for graphene liquid cell project. We needed the thick nitride to customize surface geometry of the TEM grid which would be covered by our graphene. 

Reference #220926 for specs and pricing.

What is the Difference Between Low Stress and Super Low Stress Silicon Nitride Wafers?

A nanofab engineer requested the following quote:

"Hi there, I have a quick question. What is the difference in stress level between "low- stress" and "super low-stress" LPCVD Nitride Silicon substrates? I'll meet nanofab engineer this Thursday to discuss what silicon wafers are required for RIE etching process. Meanwhile, can you give me quotes for two types of substrates?

  1. nitride (100 nm, super low-stress LPCVD)/Si (500 micron)/nitride (100 nm, standard)
  2. nitride (100 nm, super low-stress LPCVD)/Si (500 micron)/SiO2 (300 nm, thermal)
    * Other specs (for diameter, resistivity and etc.) are same as the product ID # 1922 (please see attached).

I'll decide what I need based on the price and discussion with a nanofab engineer."

The Difference Between Low Stress and Super Low Stress Nitride

Low Stress LPCVD Silicon Nitride <250 MPa tensile

Super Low Stress LPCVD Silicon Nitride <100 MPa tensile

Reference# 213220 for specs and pricing.

This paper focuses on low stress silicon nitride films (LS - SiN) and investigates the effects of high temperature and low voltage deposition conditions on the characterization of residual stresses reported in this paper. The experiments were conducted to investigate the effect of the deposition of polysilicon (silicon nitrite) under a variety of process conditions. For example, residual stresses vary considerably between the different deposition conditions. At these two temperatures, the tension is always tensile, but at 850C we observe a significant increase in the residual pressure (RI) of the film. We found that the RI increases with temperature, with an increase of up to 1,000 degrees Celsius (2,500 degrees F), and we found an increased RI of 3,200 degrees C (4,600 degrees F). [Sources: 0, 2]

The emerging semiconductor devices with large band gaps, such as those built from the SiN system, are significant because they have the potential to revolutionize the power electronics industry. As MEMS devices become smaller, a reduced residual voltage level will improve the performance and reliability of the devices. The high-temperature return loosens the load and causes the material to settle at the grain boundary, where defects and voids occur at the grain boundaries and cause a return flow. [Sources: 2, 3]

The main objective of this invention is to create the ability to produce a silicon membrane by using a selective doping scheme to define a low stress structure. The aim of the invention was to provide a method for producing high-temperature reflux silicon nitride wafers and manufactured silicon diodes with controlled thickness and low voltage. [Sources: 5]

In the plasma deposition of silicon nitride, the hydrogen is simply integrated into the silicon wafer and a thin layer is formed without tensile stress. The wafers are then etched to a nitride membrane, which serves as a supporting membrane to increase its rigidity. [Sources: 1, 5]

In this experiment, the residual stress of the polysilicon is closely related to the membrane, which is stoichiometric and not low loaded. This microstructure is highly dependent on the deposition conditions, but since the stress is so low, it does not matter. [Sources: 2, 7]

The silicon membrane thickness is 28 micrometers, which makes it possible to integrate an integrated circuit on a wafer. The resulting thickness is difficult to control and it is not easy to dilute the entire wafer by 5 - 10 microns. The stress of the deposited layer is caused by stacking errors in the crystal structure and needle holes. [Sources: 1, 5]

This method also affects residual stress and is not a good choice if a higher thickness is required for a particular application. For this application, the thin film used must be stress-free or stress-compensated. The work will be presented at the annual meeting of the American Society of Materials Science and Engineering (ASSE) in San Francisco. [Sources: 0, 2]

WO 00 - 70630) shows a powerful MEMS electret Microphone with a layer of extremely low-load silicon nitride wafers (ST). Microphone microphone describes a method of making a microphone from epitaxial silicon substrates without forming holes. The membrane itself is a low-stress ST - silicon - nitrite, in contrast to the stoichiometric ST - nitride layer, which originates from an earlier technology window in which significant stresses occur. Remember that pressure is applied to push the membrane against the silicon substrate (e.g. peel off). [Sources: 4, 5]

The tensions are inherently tensile, since the kinetic energy of the silicon atoms is low and causes nucleation at small fine grain boundaries. [Sources: 2]

The type of deposited film is either amorphous or crystalline, and the deposition rate is slow - beeswax, but the tensile stress values are significantly lower. This often leads to stress in the compression film at deposit temperatures, which cannot be explained by a relaxation of tension alone. The weak binding force of the carrier material on the film causes very little stress than the tensile stresses. If we reverse the flow ratio to 10: 1, the silicon-rich nitride layers are deposited at a very low flow rate of 1: 10,000, which affects the residual voltage shown in Figures 8 and 9 [15-19]. [Sources: 0, 2]

The values of n-2 in wafer # 01 are consistent with the data already mentioned in the literature on silicon nitride waveguides 30,31. [Sources: 6]

A three-dimensional structure whose functionality typically requires functionality that should be freed from the planar substrate. The film pattern on the surface of the micromachining process has proven to be a high quality image of a silicon nitride waveguide with a thickness of less than 1 mm. Originally used in integrated circuits, films made of thin layers of silicon oxide and a thin layer of copper oxide were deposited or removed and deposited on silicon wafers. In the LPCVD system, the thin layer on the side of each silicon wafer is deposited, and etching this layer on the back requires extremely low pressure, high temperatures and low pressure. This provides a new approach to manufacturing silicon baking plates for a wide range of applications, such as microfluidic devices and microelectronics. [Sources: 0, 2, 5]


[0]: https://www.hindawi.com/journals/amse/2013/835942/

[2]: https://www.hindawi.com/journals/jma/2014/954618/

[3]: https://jsmimmobilier.ma/kq1zq/semiconductor-device-simulation.html

[4]: https://www.2spi.com/item/4128sn-ba/

[5]: https://patents.google.com/patent/US20040253760A1/en

[6]: https://www.nature.com/articles/s41598-017-00062-6

Silicon Nitride Specifications

  • Thickness range: 50Å – 2µm
  • Thickness tolerance: +/-5%
  • Within wafer uniformity: +/-5% or better
  • Wafer to wafer uniformity: +/-5% or better
  • Sides processed: both
  • Refractive index: 2.20 +/-.02
  • Film stress: <250MPa Tensile Stress
  • Wafer size: 50mm, 100mm, 125mm, 150mm, 200mm
  • Wafer thickness: 100µm – 2,000µm
  • Wafer material: Silicon, Silicon on Insulator, Quartz
  • Temperature: 820C°
  • Gases: Dichlorosilane, Ammonia
  • Equipment: Horizontal vacuum furnace

Low Stress Silicon Nitirde on Silicon Wafer (SiN) for Research Etching and Coating Processes

A Nanotechnology researcher requested a quote for the following:

We would like to buy some low-stress SiN on Si wafer. We want to use the wafer to develop some etching and coating process that will be transferred to a SiN TEM grid that we purchased from elsewhere. Therefore, we want to find product with similar SiN properties, such as stress, Si:N stoichiometry etc., to that of the SiN TEM grid. A thick coating is preferred since we are going to use it to study the etching rate and the surface properties after etching.

Please find the specifications of the SiN TEM grid in the attached PDF. Could you please suggest some options in stock? Please let me know if you need other or more detailed information about the SiN membrane on the TEM grid.

UniversityWafer, Inc. Quoted:

For this item,the package was for qty. 12pcs,Then,the packaging was clean and vacuum sealed,If opened for qty. 5pcs only,The wafers will be contaminated,Therefore,For this item we hope to 12pcs to sell.

Silicon Diameter: 100mm Growth
Method: Cz
Type/Dopant: N/Phosphorus
Orientation: <1-0-0>
Resistivity: 1-100 ohm-cm
Thickness: 360 +/- 10 um
Front Surface: Polished
Back Surface:
Polished Flats: 2 per SEMI Std.
Primary Flat Alignment: +/- 0.5 degrees
Deposited: 10,000Å Low Stress LPCVD Silicon Nitride ± 5% @ both sides
Qty. 12pcs

Reference #263443 for specs and pricing.