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CN-116990374-B - MOSFET gas sensor and preparation method thereof

CN116990374BCN 116990374 BCN116990374 BCN 116990374BCN-116990374-B

Abstract

The application relates to a MOSFET gas sensor which comprises a substrate, a semiconductor layer, an insulating medium layer, a passivation layer, a gas-sensitive layer and a grid region notch, wherein the substrate is made of doped semiconductor materials, the surface of the semiconductor layer is provided with a channel, one end of the semiconductor layer is provided with an active region, the other end of the semiconductor layer is provided with a drain region, the insulating medium layer is positioned between the substrate and the semiconductor layer and is used for electrically separating the semiconductor layer from the substrate, the source electrode and the drain electrode are respectively arranged in the source region and the drain region, the passivation layer covers the semiconductor layer and part of the insulating medium layer, the gas-sensitive layer covers the channel region, one side of the semiconductor layer is provided with the grid region notch, the insulating medium layer penetrates through the grid region notch, and the grid electrode is arranged at the grid region notch of the substrate. The application has the effect of providing the sensitivity of the gas sensor.

Inventors

  • JIN BO
  • CHEN LEI
  • JIN JIE
  • XU JIANTAO

Assignees

  • 浙江朗德电子科技有限公司

Dates

Publication Date
20260505
Application Date
20230803

Claims (9)

  1. 1. A MOSFET gas sensor, comprising: a substrate (100) of doped semiconductor material; A semiconductor layer (300) provided with a channel (301) on the surface, wherein an active region (300 a) is arranged at one end of the channel (301) of the semiconductor layer (300), and a drain region (300 b) is arranged at the other end of the channel; an insulating dielectric layer (200) located between the substrate (100) and the semiconductor layer (300) for electrically separating the semiconductor layer (300) from the substrate (100); The passivation layer (400) is covered on the semiconductor layer (300) and part of the insulating medium layer (200), and the passivation layer (400) is provided with notches in the source region (300 a) and the drain region (300 b); a source electrode (501) covering the metal layer of the source region (300 a); a drain electrode (502) which covers the metal layer of the drain region (300 b); a gas-sensitive layer (600) which is located above the channel (301) and covers the channel (301) region; The passivation layer (400) is provided with a gate region notch (400 c) at one side of the channel (301), the gate region notch (400 c) penetrates through the insulating medium layer (200), a metal layer is covered at the gate region notch (400 c) of the substrate (100) to form a grid (503), and the passivation layer (400) is provided with a channel region notch (400 d) at the channel (301) region to enable the channel (301) region of the semiconductor layer (300) to be in direct contact with the gas-sensitive layer (600).
  2. 2. A MOSFET gas sensor according to claim 1 wherein said substrate (100) and semiconductor layer (300) are both made of silicon material, and said insulating dielectric layer (200) is silicon oxide.
  3. 3. A MOSFET gas sensor according to claim 2, wherein the trenches (301) are rectilinear, triangular, rectangular, hexagonal or circular in shape, each trench (301) being 10-500 nm wide and 50-5 um long.
  4. 4. A MOSFET gas sensor according to claim 3, wherein said semiconductor layer (300) is formed by CVD deposited silicon process or SOI manufacturing process, and the thickness of said semiconductor layer (300) is 10-200 nm.
  5. 5. A MOSFET gas sensor according to claim 4, wherein the semiconductor layer (300) is formed by bonding a wafer having the semiconductor layer (300) and the insulating dielectric layer (200) to a wafer having the substrate (100) and the insulating dielectric layer (200) by physical bonding, by using an SOI manufacturing process, the insulating dielectric layer (200) to a wafer having the substrate (100), the insulating dielectric layer (200), and the semiconductor layer (300).
  6. 6. A MOSFET gas sensor according to claim 1, wherein the gas sensitive layer (600) material is a nano-film or nano-particle of gold, silver, platinum, silicon oxide, silicon nitride, zinc oxide, titanium oxide, zirconium oxide, aluminum oxide, cerium oxide, tin oxide, indium oxide, tungsten oxide, copper oxide, nickel oxide, cobalt oxide, manganese oxide.
  7. 7. A MOSFET gas sensor according to claim 1, wherein the gas sensitive layer (600) material is formed by physical vapor deposition, chemical vapor deposition, sputter deposition, spin coating or spray coating, and the thickness of the gas sensitive layer (600) is less than 10nm.
  8. 8. A method for manufacturing a MOSFET gas sensor, applied to the MOSFET gas sensor according to any one of claims 1 to 7, characterized in that: S1, providing a substrate (100); S2, arranging an insulating medium layer (200) on the surface of the substrate (100); s3, arranging a semiconductor layer (300) on the surface of the insulating medium layer (200); s4, forming a channel (301) on the surface of the semiconductor layer (300) through a photoetching process dry etching or wet etching process; S5, forming a passivation layer (400), and forming the passivation layer (400) on the upper surfaces of the semiconductor layer (300) and the insulating medium layer (200); S6, forming gaps on the surface of the passivation layer (400) through a photoetching process, a dry etching process or a wet etching process respectively, arranging a source region (300 a) and a drain region (300 b) at two ends of a channel (301) and a gate region positioned at one side of the channel (301), and etching an insulating medium layer (200) at the gap (400 c) of the gate region; S7, doping the substrate (100) of the source region (300 a), the drain region (300 b) semiconductor layer (300) and the gate region through an ion implantation process; S8, setting an electrode, forming a source electrode (501) on the surface of a source region (300 a) of the semiconductor layer (300), forming a drain electrode (502) on the surface of a drain region (300 b) of the semiconductor layer (300), and forming a grid electrode (503) on the surface of the substrate (100) in a grid region notch (400 c) through a metal physical or chemical deposition process, a metal etching process or a metal stripping process; And S9, depositing a gas sensitive layer (600), and depositing a gas sensitive material film at a position above the channel (301) to form the gas sensitive layer (600).
  9. 9. The method of manufacturing a MOSFET gas sensor as set forth in claim 8, wherein no passivation layer (400) is left between the gas sensitive layer (600) and the channel (301) by an etching process to form a channel region gap (400 d).

Description

MOSFET gas sensor and preparation method thereof Technical Field The application relates to the field of gas sensors, in particular to a MOSFET gas sensor and a preparation method thereof. Background A metal-oxide-semiconductor field effect transistor (MOSFET) gas sensor is a common gas detection and measurement device. The method utilizes the interaction between the gas and the semiconductor surface to detect and measure the concentration of the gas, and is widely applied to the fields of environmental monitoring, industrial control, biological medicine, safety and the like. Currently, common MOSFET gas sensors include: A substrate made of a semiconductor material, on which source and drain regions are formed; A dielectric layer over the substrate, typically using an insulating material such as silicon oxide (SiO 2); And the grid electrode is positioned above the dielectric layer and plays a role in controlling the charge distribution and conductivity of the sensor. The grid electrode can adjust the sensitivity and the working state of the gas sensor by applying different voltages; the gas sensitive layer is positioned above the grid and is directly exposed in a gas environment; And the source electrode and the drain electrode are used for measuring output current, and form a P-N junction with a region on the substrate so as to form a current channel. When the target gas contacts the sensor, chemical reaction or adsorption occurs with the gas sensitive layer. This reaction causes a change in the electrical properties of the gas sensitive layer, affecting the charge distribution on the gate electrode. The change in the charge distribution on the gate affects the electric field distribution between the gate and the gas sensitive layer, thereby changing the relationship between the gate current and the drain current. By measuring the current change between the source and drain, information about the concentration of the target gas can be inferred. In view of the related art described above, the inventors have provided another new MOSFET gas sensor capable of improving the sensitivity of the gas sensor. Disclosure of Invention In order to improve the sensitivity of a gas sensor, the application provides a MOSFET gas sensor and a preparation method thereof. On one hand, the MOSFET gas sensor provided by the application adopts the following technical scheme: a MOSFET gas sensor, comprising: A substrate which is made of doped semiconductor materials; The semiconductor device comprises a substrate, a semiconductor layer, an insulating medium layer, a first insulating layer, a second insulating layer, a first insulating layer and a second insulating layer, wherein the surface of the semiconductor layer is provided with a channel, and one end of the semiconductor layer is provided with an active region while the other end is provided with a drain region; the passivation layer is covered on the semiconductor layer and part of the insulating medium layer, and notches are formed in the source region and the drain region of the passivation layer; a source electrode, a metal layer covering the source region; A drain electrode, a metal layer covering the drain region; a gas sensitive layer located above the channel and covering the channel region; The passivation layer is provided with a gate region notch at one side of the channel, the gate region notch penetrates through the insulating medium layer, and the substrate is covered with a metal layer at the gate region notch to form a gate. By adopting the technical scheme, the semiconductor layer with the channel on the insulating medium layer does not bear the function of the substrate compared with the semiconductor layer in the background art, so that the semiconductor layer with the thinner thickness can be obtained through a deposition process, the dimension of the channel can be reduced, the transconductance characteristic is improved, the subthreshold swing is reduced, the gate control capability of the MOS tube is improved, and the sensitivity of the sensor is favorably provided. In addition, the channel is not covered by the grid electrode, the gas-sensitive layer is covered above the channel, when target gas and the sensitive layer are subjected to chemical reaction or adsorption, the reaction causes the change of the electrical property of the sensitive layer, and then the electric field distribution at the channel is directly influenced, the change of drain current is directly influenced, and the grid electrode voltage is not obviously changed at the moment, so that the sensor can be controlled in the optimal detection pressure interval, and the sensitivity is improved. Optionally, the substrate and the semiconductor layer are made of silicon material, and the insulating dielectric layer is silicon oxide. Optionally, the shape of the channels is linear, triangular, rectangular, hexagonal or circular, the width of each channel is 10-500 nm, and the length of eac