Photoconductive switch that reduces on-resistance and preparation method thereof

A technology of photoconductive switch and on-resistance, which is applied in the direction of circuits, electrical components, semiconductor devices, etc., can solve the problems of not paying attention to the energy utilization of devices, etc., to reduce the on-resistance, improve the working life and stability, and enhance the absorption efficiency Effect

Active Publication Date: 2017-11-21

SHANDONG UNIV

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AI-Extracted Technical Summary

Problems solved by technology

The technical solution of this patent document only considers the withstand voltage capability of the device ...

Abstract

The invention relates to a photoconductive switch that reduces on-resistance and a preparation method thereof. The photoconductive switch comprises a gallium arsenide substrate. An antireflection film is arranged on one surface of the substrate. Electrodes are respectively arranged on two sides of the other surface of the substrate. A high-reflective film is arranged between the two electrodes. The invention also provides a method for evaporating the high-dielectric antireflection film and the high-reflective film respectively on the surfaces of the gallium arsenide substrate to reduce the on-resistance of the gallium arsenide photoconductive switch. The lower on-resistance enables the energy loss of a switching device to be reduced when the switching device operates at high power and high frequency, and the operating life and stability of the switch are improved.

Application Domain

Final product manufactureSemiconductor devices

Technology Topic

Energy lossPhotoconductive switch +7

Image

Examples

Experimental program(2)

Example Embodiment

[0046] Example 1:

[0047] A photoconductive switch with reduced on-resistance, with a structure such as figure 1 , 2 As shown, it includes a semi-insulating gallium arsenide substrate 2, an anti-reflection film 1 is provided on one side of the substrate 2, electrodes 3 are provided on both sides of the other side, and a high reflection film 5 is provided between the two electrodes.

[0048] The gallium arsenide substrate has a thickness of 600 μm and a dark state resistivity of 5*10 8 Ωcm, electron mobility 4500cm 2 /vs.

[0049] The anti-reflection coating is an optical anti-reflection coating with a reflectivity of less than 0.5% for a wavelength of 1064nm, and the anti-reflection coating is as follows: the first layer is Al with a thickness of 100-200 angstroms 2 o 3 , the second layer is ZrO with a thickness of 1000-1500 Angstroms 2 , the third layer is Al with a thickness of 800-900 angstroms 2 o 3.

[0050] The high reflection film is a film layer with a reflectivity greater than 95% for a wavelength of 1064nm. Further preferably, the antireflection film material is Al 2 o 3 with SiO 2 、TiO 2 The combination of n layers, n=13; wherein the first layer is Al with a thickness of 180-200 angstroms 2 o 3 , the second layer - the thirteenth layer is SiO 2 、TiO 2 Alternating combined layers, sequentially 2100-2400 Angstroms thick SiO 2 , 1000-1100 Angstroms TiO 2 , 2100-2200 Angstroms SiO 2 , 1000-1100 Angstroms TiO 2 , 2200-2500 Angstroms SiO 2 , 1000-1300 Angstroms TiO 2 , 2100-2300 Angstroms SiO 2 , 1000-1300 Angstroms TiO 2 , 2100-2300 Angstroms SiO 2 , 1000-1300 Angstroms TiO 2 , 2300-2600 Angstroms SiO 2 , 1000-1300 Angstroms TiO 2.

[0051] The electrode is a Ti/Pt/Au composite metal layer.

[0052] The above-mentioned photoconductive switch is packaged on the aluminum nitride ceramic sheet 7 through epoxy resin 6, and a copper foil 4 is provided between the aluminum nitride ceramic sheet and the electrode.

[0053] Preparation method, the steps are as follows:

[0054] (1) Select a semi-insulating gallium arsenide substrate with a thickness of 600um and a dark state resistivity greater than 1*10 8 Ωcm, electron mobility greater than 4000cm 2 /vs.

[0055] On the gallium arsenide substrate, p-type gallium arsenide (p-GaAs) highly doped with zinc is grown with a thickness of 300 nm by MOVPE technology. The concentration of doped zinc or carbon is 5×10 19 cm -3.

[0056] (2) Make photoconductive switch electrode pattern on the substrate by photolithography process, the electrode spacing is 10mm, and the electrode size is: 9cm (length)×4.5cm (width).

[0057] (3) Evaporate the Ti/Pt/Au metal layer of the photoconductive switch with the electrode pattern by electron beam, and remove the glue by acetone to obtain the whole gallium arsenide wafer with the electrode structure of the photoconductive switch.

[0058] (4) Using H 3 PO 4 :H 2 o 2 :H 2 The solution of O=1:1:5 was etched at 0°C for 1 min to remove excess zinc-doped p-GaAs.

[0059] (5) Perform rapid annealing on the wafer at 400° C. for 5 minutes in a nitrogen atmosphere using a rapid annealing furnace.

[0060] (6) Use vacuum coating technology to vapor-deposit anti-reflection film on the side of the non-electrode pattern. After the evaporation is completed, use temperature-resistant adhesive strips to protect the electrode area, and then use vacuum coating technology to vapor-deposit high-reflection film.

[0061] (7) Cut the prepared gallium arsenide substrate with optical film according to the pattern requirements by using DISCO saw blade machine.

[0062] (8) Encapsulate the cut photoconductive switch on the aluminum nitride ceramic sheet with epoxy resin, and the device is finished.

Example Embodiment

[0063] Example 2: Photoconductive switch on-resistance test experiment

[0064] The test circuit diagram used in the photoconductive switch on-resistance test experiment is as follows: Figure 5 As shown, R is the current limiting resistor 100MΩ, R load is a high-frequency non-inductive resistor 50Ω, C is an energy storage capacitor 1nF, and PCSS represents a photoconductive switch. Test the voltage value through the high-voltage probe, and test the current value through the current loop.

[0065] The structure made in embodiment 2 is tested on the photoconductive switch described in embodiment 1, and the waveform curves of the input voltage, output voltage and load current of the obtained results are as follows Figure 4 shown.

[0066] The gallium arsenide photoconductive switch with no evaporated anti-reflection film and high reflection film whose other structures are the same as in Example 1 was tested, and the waveform curves of the input voltage, output voltage and load current of the obtained results are as follows Figure 5 shown.

[0067] The on-resistance of the gallium arsenide photoconductive switch of the present invention is 0.49Ω, and the on-resistance of the photoconductive switch without evaporation anti-reflection film and high-reflection film is 3.3Ω.

PUM

Property	Measurement	Unit
Thickness	500.0 ~ 700.0	µm
Electron mobility	<= 4000.0	cm2/vs
Thickness	200.0 ~ 350.0	nm

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Improve absorption efficiency

Photovoltaic energy storage electric automobile charging station system and method for switching state of energy storage system

ActiveCN102361334AImprove economic efficiencyImprove absorption efficiency

Owner:SHENZHEN POWER SUPPLY BUREAU +1

Photoconductive switch that reduces on-resistance and preparation method thereof

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Image

Examples

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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