# US 10,312,345 B2 · Transistor having a gate with a variable work function and method for manufacturing the same

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- Number: US 10,312,345 B2
- Document ID: US10312345B2
- Status: Granted
- Kind: B2
- Application number: 15/871,690
- Filed: 2018-01-15
- Published: 2018-10-11
- Granted: 2019-06-04
- Earliest claimed: 2017-04-11
- Assignees: Institute of Microelectronics, Chinese Academy of Sciences
- Applicants: Institute of Microelectronics, Chinese Academy of Sciences
- Inventors: Jinjuan Xiang; Xiaolei Wang; Hong Yang; Shi Liu; Junfeng Li; Wenwu Wang; Chao Zhao
- Web page: https://patentgrep.com/patent/US10312345B2

## CPC

- H10D 64/017: {using dummy gates in processes wherein at least parts of the final gates are self-aligned to the dummy gates, i.e. replacement gate processes}
- H10D 30/60: Insulated-gate field-effect transistors [IGFET] (H10D30/40 takes precedence)
- H10D 64/01318: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN (comprising a layer of alloys of Si, Ge or C H10D64/01314)}
- H10D 64/667: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN workfunction layers (having lateral variation H10D64/671)}
- H10P 30/20: into semiconductor materials, e.g. for doping
- H10D 64/669: {the conductor further comprising additional layers of alloy material, compound material or organic material, e.g. TaN/TiAlN}
- 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 transistor having a gate with a variable work function, comprising: providing a semiconductor substrate; forming a dummy gate stack on the semiconductor substrate and performing ion implantation on an exposed area of the semiconductor substrate at both sides of the dummy gate stack to form source/drain regions; removing the dummy gate and annealing the source/drain regions; providing an atomic layer deposition reaction device; introducing a precursor source reactant into the atomic layer deposition reaction device; and controlling an environmental factor for the atomic layer deposition device to grow a work function metal layer. The present disclosure also provides a transistor having a gate with a variable work function. The present disclosure may adjust a variable work function, and may use the same material system to obtain an adjustable threshold voltage within an adjustable range.

## Claims

### Claim 1

A method for manufacturing a transistor having a gate with a variable work function, comprising:
providing a semiconductor substrate;
forming a dummy gate stack on the semiconductor substrate and performing ion implantation on an exposed area of the semiconductor substrate at both sides of the dummy gate stack to form source/drain regions;
removing the dummy gate and annealing the source/drain regions;
providing an atomic layer deposition reaction device;
introducing a precursor source reactant into the atomic layer deposition reaction device; and
controlling an environmental factor for the atomic layer deposition reaction device to grow a work function metal layer with a tunable work function.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the environmental factor for the atomic layer deposition reaction device comprises any one of a ratio of the precursor source reactant, a pulse sequence, a growth temperature and a growth thickness or a combination thereof.

### Claim 3 (depends on 2)

The method according to claim 2, wherein a material for the work function metal layer is titanium alloy or tantalum alloy.

### Claim 4 (depends on 3)

The method according to claim 3, wherein a material for the work function metal layer is TiAlC(N) or TaAlC(N).

### Claim 5 (depends on 4)

The method according to claim 4, wherein the precursor source reactant for tantalum in TaAlC(N) is tantalum halide and/or PDMAT, the precursor source reactant for Al is trialkylaluminum, alkylaluminoxane and/or ammonia coordinated alumoxane, and the precursor source reactant for nitrogen is NH3 and/or N2.

### Claim 6 (depends on 2)

The method according to claim 2, wherein the ratio of the precursor source reactant comprises a ratio of the amounts of NH3 and/or N2.

### Claim 7 (depends on 2)

The method according to claim 2, wherein the pulse sequence comprises a participating pulse sequence of NH3 and N2.

### Claim 8 (depends on 2)

The method according to claim 2, wherein the growth temperature is adjusted which may change an aluminum content ratio of the work function metal layer.

### Claim 9 (depends on 2)

The method according to claim 2, wherein the atomic layer deposition may be a heating type of atomic layer deposition or a plasma enhanced atomic deposition.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the precursor source reactant for titanium in TiAlC(N) is titanium halide and/or TDMAT, the precursor source reactant for aluminum is trialkylaluminum, alkylaluminoxane and/or ammonia coordinated alumoxane, and the precursor source reactant for nitrogen is NH3 and/or N2.