Silicon carbide-based full-spectrum-responsive photodetector and method for producing same

Patent metadata

Field	Value
Publication number	US-11710801-B2
Application number	US-202117514526-A
Country	US
Kind code	B2
Filing date	Oct 29, 2021
Priority date	Mar 12, 2021
Publication date	Jul 25, 2023
Grant date	Jul 25, 2023

Abstract

The present application relates to semiconductor photodetectors, in particular to a silicon carbide-based UV-visible-NIR full-spectrum-responsive photodetector and a method for fabricating the same. The photodetector includes a silicon carbide substrate, and metal counter electrodes and a surface plasmon polariton nanostructure arranged thereon. The silicon carbide substrate and the metal counter electrodes constitute a metal-semiconductor-metal photodetector with coplanar electrodes. When the ultraviolet light is input, free carriers directly generated in silicon carbide are collected by an external circuit to generate electrical signals. When the visible light is input, hot carriers generated in the surface plasmon polariton nanostructure tunnel into the silicon carbide semiconductor to become free carriers to generate electrical signals.

First claim

What is claimed is:

1. A silicon carbide-based full-spectrum-responsive photodetector, comprising:
a silicon carbide substrate;
wherein a silicon surface of the silicon carbide substrate is provided with a plurality of metal counter electrodes and a surface plasmon polariton nanostructure; the plurality of metal counter electrodes are arranged on the silicon carbide substrate; the surface plasmon polariton nanostructure is arranged between the plurality of metal counter electrodes; the surface plasmon polariton nanostructure comprises a plurality of metal nanoparticles uniformly distributed on the silicon surface of the silicon carbide substrate; and a Schottky contact is formed between the plurality of metal counter electrodes and the silicon carbide substrate;
wherein the surface plasmon polariton nanostructure is an array structure of the plurality of metal nanoparticles; the array structure of the plurality of metal nanoparticles has a period of 50-1000 nm; the plurality of metal nanoparticles are cubic nanoparticles or cylindrical nanoparticles; the plurality of metal nanoparticles have a side length of 20-500 nm or a diameter of 20-500 nm; and the plurality of metal nanoparticles each have a height of 20-500 nm.

2. The silicon carbide-based full-spectrum-responsive photodetector of claim 1 , wherein the plurality of metal counter electrodes are interdigital electrodes; and the surface plasmon polariton nanostructure is uniformly distributed between the interdigital electrodes.

3. The silicon carbide-based full-spectrum-responsive photodetector of claim 2 , wherein the silicon carbide substrate is made of a semi-insulating 4H-SiC, and has an intrinsic carrier concentration of 1e13/cm 3 -1e15/cm 3 and a thickness of 100-800 μm; the plurality of metal counter electrodes are made of gold, silver, titanium, nickel, palladium or cadmium; and the interdigital electrodes each have a finger width of 100-300 μm, a finger spacing of 100-300 μm, an effective area of 0.1 cm 2 and 5-15 pairs of electrodes.

4. The silicon carbide-based full-spectrum-responsive photodetector of claim 1 , wherein the plurality of metal counter electrodes are Cr/Pd double-layer electrodes or Ag/Ti double-layer electrodes.

5. The silicon carbide-based full-spectrum-responsive photodetector of claim 1 , wherein the plurality of metal nanoparticles each have a Cr/Au double-layer structure.

6. A silicon carbide-based full-spectrum-responsive photodetector, comprising:
a silicon carbide substrate;
wherein a silicon surface of the silicon carbide substrate is provided with a plurality of metal counter electrodes and a surface plasmon polariton nanostructure; the plurality of metal counter electrodes are arranged on the silicon carbide substrate; the surface plasmon polariton nanostructure is arranged between the plurality of metal counter electrodes; the surface plasmon polariton nanostructure comprises a plurality of metal nanoparticles uniformly distributed on the silicon surface of the silicon carbide substrate; and a Schottky contact is formed between the plurality of metal counter electrodes and the silicon carbide substrate;
wherein the surface plasmon polariton nanostructure is a randomly-distributed island-shaped metal nanoparticle structure formed by annealing of a metal film; metal islands of the randomly-distributed island-shaped metal nanoparticle structure have an average diameter of 20-100 nm; and an average size of a gap between the metal islands is 50-300 nm.

7. A method of producing a silicon carbide-based full-spectrum-responsive photodetector, the silicon carbide-based full-spectrum-responsive photodetector comprising:
a silicon carbide substrate;
wherein a silicon surface of the silicon carbide substrate is provided with a plurality of metal counter electrodes and a surface plasmon polariton nanostructure; the plurality of metal counter electrodes are arranged on the silicon carbide substrate; the surface plasmon polariton nanostructure is arranged between the plurality of metal counter electrodes; the surface plasmon polariton nanostructure comprises a plurality of metal nanoparticles uniformly distributed on the silicon surface of the silicon carbide substrate; and a Schottky contact is formed between the plurality of metal counter electrodes and the silicon carbide substrate;
the method comprising:
(S1) calibrating a carbon surface and the silicon surface of the silicon carbide substrate by using an atomic force microscope; and cleaning and drying the silicon carbide substrate;
(S2) distributing the plurality of metal nanoparticles evenly on the silicon surface of the silicon carbide substrate to form the surface plasmon polariton nanostructure; and
(S3) preparing the plurality of metal counter electrodes on both sides of the surface plasmon polariton nanostructure to produce the silicon carbide-based full-spectrum-responsive photodetector.

8. The method of claim 7 , wherein the step (S2) is performed through steps of:
putting the silicon carbide substrate into a magnetron sputtering coating chamber; coating a gold film with a thickness of 5 nm by sputtering at a rate of 0.1 nm/s on a side of the silicon carbide substrate where the silicon surface is located; transferring the silicon carbide substrate coated with the gold film to a muffle furnace; heating the muffle furnace to 500° C.; and cooling the muffle furnace to room temperature in an equal step manner within two hours to form island-shape gold nanoparticles; and
the step (S3) is performed through steps of:
loading a mask on the silicon carbide substrate, and depositing a metal layer on the silicon carbide substrate by evaporation; and
removing the mask to complete a preparation of the plurality of metal counter electrodes.

9. The method of claim 7 , wherein the step (S2) is performed through steps of:
coating a polymethyl methacrylate (PMMA) photoresist film with a thickness of 80 nm on the silicon surface of the silicon carbide substrate through spin coating; and exposing the silicon carbide substrate coated with the PMMA photoresist film by deep ultraviolet lithography or electron beam lithography; wherein an exposure pattern is consistent with a pattern of the surface plasmon polariton nanostructure;
immersing the silicon carbide substrate into a developer solution for fixing followed by rinsing and blow drying; and
producing a Cr adhesion layer with a thickness of 5 nm and an Au film with a thickness of 50 nm on a surface of the silicon carbide substrate by magnetron sputtering; immersing the silicon carbide substrate in acetone to peel off unexposed PMMA photoresist and Cr and Au thereon; and subjecting the silicon carbide substrate to blow drying to complete preparation of the surface plasmon polariton nanostructure.

Assignees

• Univ Taiyuan Technology

Inventors

• Cui Yanxia
• Fan Yaping
• Yan Xianyong
• Li Guohui
• Tian Yuan

Classifications

• H10F77/122

  comprising only Group IV materials · CPC title

• H10F77/206

  for devices having potential barriers · CPC title

• H10F30/2275 Primary

  being a metal-semiconductor-metal [MSM] Schottky barrier · CPC title

• H10F30/10

  the devices being sensitive to infrared radiation, visible or ultraviolet radiation, and having no potential barriers, e.g. photoresistors · CPC title

• H10F77/20

  Electrodes · CPC title