# US 9,520,286 B2 · Semiconductor substrate, semiconductor device and method of manufacturing the semiconductor device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,286 B2 - Document ID: US9520286B2 - Status: Granted - Kind: B2 - Application number: 14/892,034 - Filed: 2014-05-02 - Published: 2016-04-21 - Granted: 2016-12-13 - Earliest claimed: 2013-05-31 - Assignees: Shanken Electric Co., Ltd.; Shin-Etsu Handotai Co., Ltd. - Applicants: Sanken Electric Co., Ltd.; Shin-Etsu Handotai Co., Ltd. - Inventors: Hiroshi Shikauchi; Ken Sato; Hirokazu Goto; Masaru Shinomiya; Keitaro Tsuchiya; Kazunori Hagimoto - Web page: https://patentgrep.com/patent/US9520286B2 ## CPC - H10P 14/3416: {Nitrides} - H10D 30/015: {of FETs having heterojunction interface channels or heterojunction gate electrodes, e.g. HEMT} - H10D 30/475: {having wider bandgap layer formed on top of lower bandgap active layer, e.g. undoped barrier HEMTs such as i-AlGaN/GaN HEMTs} - H10D 30/4755: {having wide bandgap charge-carrier supplying layers, e.g. modulation doped HEMTs such as n-AlGaAs/GaAs HEMTs} - H10D 62/60: Impurity distributions or concentrations - H10D 62/8171: {Doping structures, e.g. doping superlattices or nipi superlattices} - H10D 62/824: comprising only Group III-V materials heterojunctions, e.g. GaN/AlGaN heterojunctions - H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN} - H10P 14/2904: {Silicon carbide} - H10P 14/2905: {Silicon, silicon germanium or germanium} - H10P 14/3216: {Nitrides} - H10P 14/3252: {Alternating layers, e.g. superlattice} - H10P 14/3254: {Graded layers} - H10D 62/357: {of FETs} - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract A semiconductor substrate having a silicon-based substrate, a buffer layer provided on the silicon-based substrate and made of a nitride semiconductor containing boron, and an operation layer formed on the buffer layer, wherein a concentration of boron in the buffer layer gradually decreasing toward a side of the operation layer from a side of the silicon-based substrate. Thereby, the semiconductor substrate in which the buffer layer contains boron sufficient to obtain a dislocation suppression effect and boron is not diffused to the operation layer is provided. ## Claims ### Claim 1 A semiconductor substrate comprising: a silicon-based substrate; a buffer layer provided on the silicon-based substrate and comprised of a nitride semiconductor containing boron; and an operation layer formed on the buffer layer, wherein the buffer layer has a stacked body comprising of three or more layers, and a concentration of boron in the stacked body gradually decreases toward a side of the operation layer from a side of the silicon-based substrate. ### Claim 2 (depends on 1) The semiconductor substrate according to claim 1, wherein a concentration of boron in a region at a side of the operation layer in the buffer layer is less than 5×1016 atoms/cm3. ### Claim 3 (depends on 1) The semiconductor substrate according to claim 1, wherein the buffer layer is stacked such that a first layer comprised of AlyGa1-yN and a second layer comprised of AlxGa1-xN(0≦x≦y≦1) are repeatedly stacked. ### Claim 4 (depends on 2) The semiconductor substrate according to claim 2, wherein the buffer layer is stacked such that a first layer comprised of AlyGa1-yN and a second layer comprised of AlxGa1-xN(0≦x≦y≦1) are repeatedly stacked. ### Claim 5 (depends on 1) The semiconductor substrate according to claim 1, wherein a concentration of boron of the silicon-based substrate is higher than a concentration of boron in a region at a side of the silicon-based substrate in the buffer layer. ### Claim 6 (depends on 2) The semiconductor substrate according to claim 2, wherein a concentration of boron of the silicon-based substrate is higher than a concentration of boron in a region at a side of the silicon-based substrate in the buffer layer. ### Claim 7 (depends on 3) The semiconductor substrate according to claim 3, wherein a concentration of boron of the silicon-based substrate is higher than a concentration of boron in a region at a side of the silicon-based substrate in the buffer layer. ### Claim 8 (depends on 4) The semiconductor substrate according to claim 4, wherein a concentration of boron of the silicon-based substrate is higher than a concentration of boron in a region at a side of the silicon-based substrate in the buffer layer. ### Claim 9 (depends on 1) A semiconductor device comprising: the semiconductor substrate according to claim 1; a first electrode formed on the operation layer; and a second electrode formed on the operation layer, wherein the first electrode and the second electrode are disposed such that a current flows from the first electrode to the second electrode via the operation layer. ### Claim 10 (depends on 2) A semiconductor device comprising: the semiconductor substrate according to claim 2; a first electrode formed on the operation layer; and a second electrode formed on the operation layer, wherein the first electrode and the second electrode are disposed such that a current flows from the first electrode to the second electrode via the operation layer. ### Claim 11 (depends on 3) A semiconductor device comprising: the semiconductor substrate according to claim 3; a first electrode formed on the operation layer; and a second electrode formed on the operation layer, wherein the first electrode and the second electrode are disposed such that a current flows from the first electrode to the second electrode via the operation layer. ### Claim 12 (depends on 4) A semiconductor device comprising: the semiconductor substrate according to claim 4; a first electrode formed on the operation layer; and a second electrode formed on the operation layer, wherein the first electrode and the second electrode are disposed such that a current flows from the first electrode to the second electrode via the operation layer. ### Claim 13 (depends on 5) A semiconductor device comprising: the semiconductor substrate according to claim 5; a first electrode formed on the operation layer; and a second electrode formed on the operation layer, wherein the first electrode and the second electrode are disposed such that a current flows from the first electrode to the second electrode via the operation layer. ### Claim 14 A method of manufacturing a semiconductor device comprising: forming a buffer layer comprised of a nitride semiconductor on a silicon-based substrate, the buffer layer having a stacked body comprising of three or more layers; and forming an operation layer on the buffer layer, wherein the step of forming the buffer layer comprises a stage in which boron is introduced into the buffer layer such that a concentration of boron in the buffer layer gradually decreases toward a side of the operation layer from a side of the silicon-based substrate. ### Claim 15 (depends on 14) The method of manufacturing the semiconductor device according to claim 14, wherein the stage in which boron is introduced into the buffer layer comprises a stage in which boron is diffused in the buffer layer from the silicon-based substrate in which boron is doped by thermal diffusion. ### Claim 16 (depends on 14) The method of manufacturing the semiconductor device according to claim 14, wherein the stage in which boron is introduced into the buffer layer comprises a stage in which boron is doped from a vapor phase by introducing dopant gas when the buffer layer is formed by vapor phase epitaxial growth. ### Claim 17 (depends on 15) The method of manufacturing the semiconductor device according to claim 15, wherein the stage in which boron is introduced into the buffer layer comprises a stage in which boron is doped from a vapor phase by introducing dopant gas when the buffer layer is formed by vapor phase epitaxial growth. ### Claim 18 (depends on 14) The method of manufacturing the semiconductor device according to claim 14, wherein a stacked body in which a first layer comprised of AlyGa1-yN and a second layer comprised of AlxGa1-xN(0≦x≦y≦1) are repeatedly stacked is formed as the buffer layer, and both of the first layer and the second layer contain the boron. ### Claim 19 (depends on 15) The method of manufacturing the semiconductor device according to claim 15, wherein a stacked body in which a first layer comprised of AlyGa1-yN and a second layer comprised of AlxGa1-xN(0≦x≦y≦1) are repeatedly stacked is formed as the buffer layer, and both of the first layer and the second layer contain the boron. ### Claim 20 (depends on 14) The method of manufacturing the semiconductor device according to claim 14, wherein a concentration of boron of the silicon-based substrate is made higher than a concentration of boron in a region at a side of the silicon-based substrate in the buffer layer.