# US 2019/0355585 A1 · Selective formation of titanium silicide and titanium nitride by hydrogen gas control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0355585 A1 - Document ID: US20190355585A1 - Status: Published application - Kind: A1 - Application number: 15/983,216 - Filed: 2018-05-18 - Published: 2019-11-21 - Earliest claimed: 2018-05-18 - Assignees: Taiwan Semiconductor Manufacturing Company, Ltd. - Applicants: Taiwan Semiconductor Manufacturing Co., Ltd. - Inventors: Cheng-Wei CHANG; Kao-Feng LIN; Min-Hsiu HUNG; Yi-Hsiang CHAO; Huang-Yi HUANG; Yu-Ting LIN - Web page: https://patentgrep.com/patent/US20190355585A1 ## CPC - H10D 64/0112: {using conductive layers comprising silicides} - H10D 30/024: {of fin field-effect transistors [FinFET]} - H10D 30/62: Fin field-effect transistors [FinFET] - H10D 30/6219: {characterised by the source or drain electrodes} - H10D 64/01312: {the additional layer comprising a metal or metal silicide formed by deposition, i.e. without a silicidation reaction, e.g. sputter deposition} - H10D 64/62: Electrodes ohmically coupled to a semiconductor - H10D 64/663: {the additional layers comprising a silicide layer contacting the layer of silicon, e.g. polycide gates} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract The present disclosure relates to a method for fabricating a semiconductor structure. The method includes providing a substrate with a gate structure, an insulating structure over the gate structure, and a S/D region; depositing a titanium silicide layer over the S/D region with a first chemical vapor deposition (CVD) process. The first CVD process includes a first hydrogen gas flow. The method also includes depositing a titanium nitride layer over the insulating structure with a second CVD process. The second CVD process includes a second hydrogen gas flow. The first and second CVD processes are performed in a single reaction chamber and a flow rate of the first hydrogen gas flow is higher than a flow rate of the second hydrogen gas flow. ## Claims ### Claim 1 A method for fabricating a semiconductor structure, the method comprising: forming a fin with a source/drain (S/D) region on a substrate; forming a gate structure over the fin; forming an insulating structure on the gate structure; forming a titanium silicide layer over the S/D region with a first chemical vapor deposition (CVD) process comprising a first hydrogen gas flow; and forming a titanium nitride layer over the insulating structure with a second CVD process comprising a second hydrogen gas flow, wherein the first and second CVD processes are performed in a single reaction chamber and a flow rate of the first hydrogen gas flow is higher than a flow rate of the second hydrogen gas flow. ### Claim 2 (depends on 1) The method of claim 1, wherein the forming the titanium silicide layer comprises: depositing a first titanium layer over the S/D region using the first hydrogen gas flow; and converting a portion of the first titanium layer to the titanium silicide layer using the first hydrogen gas flow. ### Claim 3 (depends on 2) The method of claim 2, wherein the forming the titanium nitride layer comprises: depositing a second titanium layer over a sidewall of the insulating structure using the second hydrogen gas flow; and converting a portion of the second titanium layer to the titanium nitride layer. ### Claim 4 (depends on 3) The method of claim 3, wherein each of the first and second CVD processes comprises a plasma-enhanced CVD (PECVD) process. ### Claim 5 (depends on 1) The method of claim 1, wherein: the flow rate of the first hydrogen gas flow is in a range of about 500 standard cubic centimeter per minute (sccm) to about 1500 sccm and the flow rate of the second hydrogen gas flow is in a range of about 5 sccm to about 50 sccm; powers of the first and second CVD processes are in a range of about 200 W to about 750 W; a flow rate of argon gas in the first CVD process is in a range of about 40 sccm to about 2500 sccm and a flow rate of argon gas in the second CVD process is in a range of about 500 sccm to about 2200 sccm; and flow rates of titanium (IV) chloride (TiCl4) gases in the first and second CVD processes are in a range of about 1 sccm to about 20 sccm. ### Claim 6 (depends on 1) The method of claim 1 wherein: the flow rate of the first hydrogen gas flow is about 1000 standard cubic centimeter per minute (sccm) and the flow rate of the second hydrogen gas flow is about 10 sccm; and a flow rate of a titanium (IV) chloride (TiCl4) gas in the first CVD process is about 3.5 sccm and a flow rate of a TiCl4 gas in the second CVD process is about 10 sccm. ### Claim 7 (depends on 1) The method of claim 1, wherein: the forming the titanium silicide layer comprises depositing the titanium silicide layer with a thickness in a range of about 7 nm to about 10 nm; and the forming the titanium nitride layer comprises depositing the titanium nitride layer with a thickness in a range of about 1 nm to about 4 nm. ### Claim 8 (depends on 3) The method of claim 3, wherein the converting the portion of the second titanium layer to the titanium nitride layer comprises nitriding the second titanium layer using ammonia gas, wherein a flow rate of the ammonia gas is in a range of about 500 standard cubic centimeter per minute (sccm) to about 5000 sccm. ### Claim 9 (depends on 1) The method of claim 1, wherein the first CVD process comprises at least one cycle, and wherein each of the at least one cycle comprises: forming at least a portion of the titanium silicide layer with a first deposition sub-process; removing a residual gas with a purge sub-process; and cleaning the substrate with a first hydrogen treatment sub-process. ### Claim 10 (depends on 9) The method of claim 9, wherein the first CVD process comprises 1 cycle to 5 cycles. ### Claim 11 (depends on 1) The method of claim 1, wherein the second CVD process comprises a forming at least a portion of the second titanium layer with a second deposition sub-process and forming the titanium nitride layer with a nitridation sub-process, and wherein a deposition time of the second deposition sub-process is in a range of about 150 seconds to about 5000 seconds. ### Claim 12 A method for fabricating a semiconductor structure, the method comprising: forming a source/drain (S/D) region on a substrate; depositing a titanium silicide layer over the S/D region with a first deposition process comprising a first hydrogen-to-precursor flow rate ratio; and depositing a titanium nitride layer over the titanium silicide layer with a second deposition process comprising a second hydrogen-to-precursor flow rate ratio, wherein the first hydrogen-to-precursor flow rate ratio is greater than the second hydrogen-to-precursor flow rate ratio. ### Claim 13 (depends on 12) The method of claim 12, wherein; a hydrogen flow rate of the first hydrogen-to-precursor flow rate ratio is in a range of about 500 standard cubic centimeter per minute (sccm) to about 1500 sccm, a precursor flow rate of the first hydrogen-to-precursor flow rate is in a range of about 1 sccm to about 20 sccm, and the first hydrogen-to-precursor flow rate ratio is in a range of about 25 to about 1500; and a hydrogen flow rate of the second hydrogen-to-precursor flow rate ratio is in a range of about 5 sccm to about 50 sccm, a precursor flow rate of the second hydrogen-to-precursor flow rate is in a range of about 1 sccm to about 20 sccm, and the second hydrogen-to-precursor flow rate ratio is in a range of about 0.25 to about 50. ### Claim 14 (depends on 13) The method of claim 13, wherein the precursor includes titanium (IV) chloride (TiCl4). ### Claim at position 15 15-20. (canceled) ### Claim 21 (depends on 1) The method of claim 1, wherein the forming the titanium silicide layer and the titanium nitride layer comprises forming a ratio of a thickness of the titanium silicide layer to a thickness of the titanium nitride layer in a range of about 3 to about 7. ### Claim 22 A method comprising: forming a fin with a source/drain (S/D) region on a substrate; forming a gate structure over the fin; forming a spacer on a sidewall of the gate structure; depositing a silicide layer on the S/D region and on a first portion of the spacer with a first deposition process comprising a first precursor gas flow; and depositing a nitride layer on a second portion of the spacer with a second deposition process comprising a second precursor gas flow, wherein the first and second deposition processes are performed in a single reaction chamber and a flow rate of the second precursor gas flow is higher than a flow rate of the first precursor gas flow. ### Claim 23 (depends on 22) The method of claim 22, wherein the depositing the silicide layer comprises: depositing a first metal layer on the S/D region and on the spacer using the first precursor gas flow and a first hydrogen gas flow; and converting a portion of the first metal layer to the silicide layer using the hydrogen gas flow. ### Claim 24 (depends on 23) The method of claim 23, wherein the depositing the nitride layer comprises: depositing a second metal layer along a sidewall of the spacer using the second precursor gas flow and a second hydrogen gas flow; and nitriding a portion of the second metal layer to the nitride layer using an ammonia gas flow. ### Claim 25 (depends on 24) The method of claim 24, wherein a flow rate of the first hydrogen gas flow is higher than a flow rate of the second hydrogen gas flow. ### Claim 26 (depends on 22) The method of claim 22, wherein the depositing the silicide layer comprises depositing a first metal layer on the S/D region and converting a first portion of the first metal layer to the silicide layer; and wherein the depositing the nitride layer comprises depositing a second metal layer on a second portion of the first metal layer.