# US 11,309,401 B2 · Method for manufacturing thin film transistor and thin film transistor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,401 B2 - Document ID: US11309401B2 - Status: Granted - Kind: B2 - Application number: 16/604,262 - Filed: 2019-04-01 - Published: 2021-10-21 - Granted: 2022-04-19 - Earliest claimed: 2018-12-19 - Assignees: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd. - Applicants: Wuhan China Star Optoelectronics Semiconductor Display Technology Co., Ltd. - Inventors: Tianyu Huang - Web page: https://patentgrep.com/patent/US11309401B2 ## CPC - H10D 30/01: Manufacture or treatment - H10D 30/675: {Group III-V materials, Group II-VI materials, Group IV-VI materials, selenium or tellurium} - H10D 62/40: Crystalline structures - H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN} - H10P 10/00: Bonding of wafers, substrates or parts of devices - H10P 30/206: {into Group III-V semiconductors} - H10P 30/21: {of electrically active species} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract The present disclosure provides a method for manufacturing a thin film transistor and a thin film transistor, which includes providing a substrate; forming an active layer on the substrate and patterning the active layer, the active layer is made of cubic boron nitride; and forming a first insulating layer, a gate electrode metal layer, a second insulating layer, a source and drain metal layer and a flat layer on the active layer successively. the method for manufacturing a thin film transistor and the thin film transistor of the present disclosure employ cubic boron nitride instead of polysilicon as active layer materials, CVD process is directly applied to form the active layer with cubic boron nitride. ## Claims ### Claim 1 A method for manufacturing a thin film transistor, comprising: providing a substrate; forming an active layer on the substrate and patterning the active layer, wherein the active layer is made of cubic boron nitride and the patterned active layer comprises a channel region and doped regions disposed at two sides of the channel region; applying a doping process to the patterned active layer; forming a first insulating layer upon the substrate; forming a gate electrode metal layer upon the substrate; forming a second insulating layer upon the substrate; and forming a source and drain metal layer upon the substrate; wherein during the step of forming an active layer on the substrate, the active layer is formed by a chemical vapor deposition method, vapor for forming the active layer comprise boron chloride, boron hydride, and ammonia; wherein the step of forming the active layer on the substrate comprises: coating a photoresist on the active layer; exposing and developing the photoresist by a mask process to form an exposing region to expose the active layer; etching the active layer disposed in the exposing region to form a patterned active layer; and removing a remaining part of the photoresist; wherein the step of applying the doping process to the patterned active layer comprises: applying a first doping treatment to the doping regions; forming the first insulating layer on the patterned active layer; forming through holes in the first insulating layer corresponding to the doping regions to expose at least a part of the doping regions; and applying a second doping treatment to the doping regions exposed by the through holes, wherein a doping amount of an element of the second doping treatment is less than one third of a doping amount of an element of the first doping treatment. ### Claim 2 (depends on 1) The method for manufacturing the thin film transistor of claim 1, wherein the doping region is an N type doping region, and a doping element of the doping region is made of a material selected from the group consisting of phosphorus, arsenic, and antimony. ### Claim 3 (depends on 1) The method for manufacturing the thin film transistor of claim 1, wherein the doping region is a P type doping region, and a doping element of the doping region is made of a material selected from the group consisting of boron and indium. ### Claim 4 (depends on 1) The method for manufacturing the thin film transistor of claim 1, wherein the doping process is an ion implantation process. ### Claim 5 (depends on 1) The method for manufacturing the thin film transistor of claim 1, wherein the source and drain metal layer is electrically connected to the doping region by the through holes. ### Claim 6 A method for manufacturing a thin film transistor, comprising: providing a substrate; forming an active layer on the substrate and patterning the active layer, wherein the active layer is made of cubic boron nitride and the patterned active layer comprises a channel region and doped regions disposed at two sides of the channel region; applying a doping process to the patterned active layer; forming a first insulating layer upon the substrate; forming a gate electrode metal layer upon the substrate; forming a second insulating layer upon the substrate; and forming a source and drain metal layer upon the substrate; wherein the step of applying the doping process to the patterned active layer comprises: applying a first doping treatment to the doping regions; forming the first insulating layer on the patterned active layer; forming through holes in the first insulating layer corresponding to the doping regions to expose at least a part of the doping regions; and applying a second doping treatment to the doping regions exposed by the through holes, wherein a doping amount of an element of the second doping treatment is less than one third of a doping amount of an element of the first doping treatment. ### Claim 7 (depends on 6) The method for manufacturing the thin film transistor of claim 6, wherein during the step of forming an active layer on the substrate, the active layer is formed by a chemical vapor deposition method, vapor for forming the active layer comprise boron chloride, boron hydride, and ammonia. ### Claim 8 (depends on 6) The method for manufacturing the thin film transistor of claim 6, wherein the step of forming the active layer on the substrate comprises: coating a photoresist on the active layer; exposing and developing the photoresist by a mask process to form an exposing region to expose the active layer; etching the active layer disposed in the exposing region to form a patterned active layer; and removing a remaining part of the photoresist. ### Claim 9 (depends on 6) The method for manufacturing the thin film transistor of claim 6, wherein the doping region is an N type doping region, and a doping element of the doping region is made of a material selected from the group consisting of phosphorus, arsenic, and antimony. ### Claim 10 (depends on 6) The method for manufacturing the thin film transistor of claim 6, wherein the doping region is a P type doping region, and a doping element of the doping region is made of a material selected from the group consisting of boron and indium. ### Claim 11 (depends on 6) The method for manufacturing the thin film transistor of claim 6, wherein the doping process is an ion implantation process. ### Claim 12 (depends on 6) The method for manufacturing the thin film transistor of claim 6, wherein the source and drain metal layer is electrically connected to the doping region by the through holes.