Terahertz Circuits Using Quartz Windows

Substrates for Terahertz Beamsplitters and THz Devices

UniversityWafer, Inc. supplies high-resistivity silicon, silicon-on-sapphire, gallium phosphide, ZnTe crystals, and quartz substrates for terahertz beamsplitters, electro-optical sampling, THz-TDS spectroscopy, and terahertz detection. Our materials support research in quantum nano-optoelectronics, photonics, and high-frequency electronics.

Float Zone Silicon for Terahertz Beamsplitters

A Quantum Nano-Optoelectronics researcher requested the following:

We need high-resistivity float zone silicon (HRFZ Si) with 50.8 mm diameter and 3 mm thickness for terahertz beamsplitters.

UniversityWafer, Inc. Quoted:

3-inch Float Zone Silicon wafer
Resistivity >10,000 Ω-cm
76.2 mm diameter
3 mm thickness
Double-side polished
Quantity: 25 pieces

Reference #269299 for specifications and pricing.

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Silicon-on-Sapphire for THz Modulation

Researchers studying deep terahertz modulation requested silicon-on-sapphire (SoS) wafers to investigate photoexcitation and modulation of THz radiation using thin silicon films.

Reference #ONL29063 for specifications and pricing.

Gallium Phosphide for Terahertz Detection

Gallium phosphide (GaP) crystals are widely used for terahertz detection and electro-optical sampling due to their excellent optical and nonlinear properties.

A postdoctoral researcher requested:

Undoped GaP (110)
10 × 10 × 0.5 mm, DSP
5 × 5 × 0.2 mm, DSP

Reference #255350 for pricing and availability.

Silicon Windows for THz-TDS Spectroscopy

A nanotechnology researcher requested high-resistivity silicon windows for time-domain spectroscopy (THz-TDS) over the 200 GHz to 5 THz range.

UniversityWafer supplied:

201 mm × 65 mm × 1.6 mm, DSP, >10K Ω-cm
201 mm × 65 mm × 3.1 mm, DSP, >10K Ω-cm
201 mm × 65 mm × 3.8 mm, DSP, >10K Ω-cm

All windows featured precision parallelism and beveled edges.

Reference #258947 for specifications and pricing.

ZnTe Crystals for Electro-Optical Sampling

Zinc Telluride (ZnTe) and GaP crystals are commonly used for terahertz electro-optical sampling.

A PhD candidate requested ZnTe (110) crystals and GaP (110) substrates with thicknesses near 0.5 mm for THz measurements.

UniversityWafer, Inc. Quoted:

GaP (110), 5 × 5 × 0.5 mm, DSP
ZnTe (110), 5 mm × 0.5 mm
ZnTe (110), 10 mm × 0.5 mm
Shipment: 6–7 weeks ARO

Reference #270778 for more information.

Double-Side Polished GaP for THz Detection

A graduate student studying terahertz detection requested:

Reference #274896 for pricing and lead time.

High-Resistivity Silicon for Terahertz Circuits

A PhD researcher studying terahertz and photonics passive circuits requested information on 8-inch high-resistivity silicon wafers with resistivities above 1 kΩ-cm. High-resistivity float-zone silicon (HRFZ Si) is widely used in THz devices because of its extremely low loss and excellent transmission characteristics.

UniversityWafer, Inc. quoted:

Item #3328
100 mm Undoped <100> Silicon
>20,000 Ω-cm resistivity
525 µm thickness
Single-side polished, prime grade

Reference #263806

What Materials Are Used for Terahertz Circuits?

Terahertz (THz) circuits operate in the frequency range between microwaves and infrared light. These devices are used in spectroscopy, imaging, wireless communications, sensors, radar systems, and quantum photonics. Material selection is critical because substrate losses directly affect device performance.

Terahertz circuit structure

Terahertz Circuit Structure

Silicon Substrates for THz Applications

Silicon wafers remain one of the most commonly used materials for terahertz circuits. High-resistivity float-zone silicon offers low dielectric loss, excellent uniformity, and compatibility with semiconductor processing technologies.

Applications include:

THz waveguides
Photoconductive antennas
THz modulators
Spectroscopy systems
Passive photonic circuits
High-speed communication devices

Gallium Arsenide (GaAs) for Terahertz Devices

Gallium arsenide (GaAs) provides higher electron mobility than silicon and is commonly used for high-frequency devices, photoconductive switches, and THz emitters. GaAs substrates are widely employed in telecommunications, solar cells, microwave electronics, and terahertz directional couplers.

Its fast carrier response makes GaAs particularly attractive for ultrafast photonics and THz generation systems.

Indium Phosphide (InP) for High-Speed THz Electronics

Indium phosphide (InP) is another III-V semiconductor frequently used in terahertz transistors, photodetectors, and high-speed optoelectronic devices. InP offers superior electron velocity and excellent performance at very high frequencies.

InP substrates are commonly used to fabricate:

Laser diodes
Photodetectors
Resonant tunneling diodes
THz integrated circuits
High-speed communication components

Silicon-on-Insulator (SOI) for THz Circuits

Silicon-on-insulator (SOI) substrates improve performance at terahertz frequencies by reducing parasitic capacitance and electrical losses. SOI technology is widely used for RF devices, millimeter-wave electronics, and integrated THz components.

The insulating oxide layer helps achieve better signal integrity and higher operating frequencies compared with conventional silicon.

Fused Quartz Windows for Terahertz Measurements

Fused quartz and fused silica windows exhibit excellent transparency throughout the terahertz spectrum. Their low thermal expansion, high chemical purity, and low dielectric loss make them ideal for THz spectroscopy, waveguides, vacuum windows, and optical systems.

Researchers often request quartz windows with diameters around 50 mm and thicknesses ranging from 0.5 mm to 2 mm for frequencies between 0.1 and 3 THz.

Thin Quartz Wafers for THz Wave Applications

Ultra-thin quartz wafers are increasingly used for specialized terahertz wave experiments. Double-side polished quartz with thicknesses below 50 µm can be fabricated for structural dynamics studies and advanced THz devices.

UniversityWafer supplied:

Single crystal quartz wafer
1-inch diameter
45.7 µm thickness
Double-side polished
Quantity: 10 pieces

Reference #272647 for specifications and pricing.

Applications of Terahertz Circuits

Terahertz electronics are enabling breakthroughs in:

Wireless communications
THz spectroscopy
Security imaging systems
Biomedical diagnostics
Radar technologies
Quantum photonics
High-speed sensors
Integrated photonic circuits
Material characterization

UniversityWafer, Inc. supplies high-resistivity silicon, quartz, gallium arsenide, indium phosphide, silicon-on-insulator, ZnTe, GaP, and other substrate materials for advanced terahertz research and production.