# US 7,745,334 B2 · Technique for locally adapting transistor characteristics by using advanced laser/flash anneal techniques

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- Number: US 7,745,334 B2
- Document ID: US7745334B2
- Status: Granted
- Kind: B2
- Application number: 11/736,939
- Filed: 2007-04-18
- Published: 2008-04-03
- Granted: 2010-06-29
- Earliest claimed: 2006-09-29
- Assignees: Advanced Micro Devices, Inc.
- Inventors: Patrick Press; Karla Romero; Martin Trentzsch; Karsten Wieczorek; Thomas Feudel; Markus Lenski; Rolf Stephan
- Web page: https://patentgrep.com/patent/US7745334B2

## CPC

- H10P 34/42: with electromagnetic radiation, e.g. laser annealing (laser cutting H10P54/20)
- H10B 10/00: Static random access memory [SRAM] devices
- H10D 30/0212: {using self-aligned silicidation}
- H10D 30/792: {comprising applied insulating layers, e.g. stress liners}
- H10D 84/0167: {Manufacturing their channels}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 30/601: {having lightly-doped drain or source extensions, e.g. LDD IGFETs or DDD IGFETs (lightly doped source or drain extensions for TFTs H10D30/6715)}
- H10D 64/015: {removing at least parts of gate spacers, e.g. disposable spacers}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10B: ELECTRONIC MEMORY DEVICES
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

By performing sophisticated anneal techniques, such as laser anneal, flash anneal and the like, for a metal silicide formation, such as nickel silicide, the risk of nickel silicide defects in sensitive device regions, such as SRAM pass gates, may be significantly reduced. Also, the activation of dopants may be performed in a highly localized manner, so that undue damage of gate insulation layers may be avoided when activating and re-crystallizing drain and source regions.

## Claims

### Claim 1

A method, comprising:
selectively modifying at least one surface characteristic of a first device region and a second device region of a semiconductor device to provide different optical responses in said first and second device regions when irradiated by a radiation of a specified wavelength range;
after selectively modifying said at least one surface characteristic, forming a first metal silicide in said first device region at a first reaction temperature created by irradiating said first device region by said radiation of said specified wavelength range; and
forming a second metal silicide in said second device region at a second reaction temperature created by irradiating said second device region by said radiation of said specified wavelength range, said first temperature being less than said second temperature, wherein irradiating said first and second device regions comprises irradiating said first and second device regions with a beam of said radiation, and wherein each surface portion irradiated by said beam is irradiated for a time interval of 0.1 seconds or less.

### Claim 2 (depends on 1)

The method of claim 1, wherein said first and second metal silicide regions comprise nickel.

### Claim 3 (depends on 1)

The method of claim 1, wherein said first and second temperatures are obtained by using different time intervals in said first and second device regions.

### Claim 4 (depends on 1)

The method of claim 1, wherein said first device regions comprises a transistor element of an SRAM cell.

### Claim 5 (depends on 1)

The method of claim 1, wherein modifying said surface characteristics comprises providing a material layer of specified optical properties in at least one of said first and second device regions to obtain said different optical response.

### Claim 6 (depends on 5)

The method of claim 5, wherein said material layer is formed in said first and second device regions and is selectively reduced in thickness in one of said first and second device regions.

### Claim 7 (depends on 6)

The method of claim 6, wherein said material layer comprises a refractory metal.

### Claim 8

A method, comprising:
selectively modifying at least one surface characteristic of a first device region and a second device region of a semiconductor device to provide different optical responses in said first device region and said second device region to a specified wavelength range of radiation, wherein said first device region represents a gate electrode of a transistor and said second device region represents at least a portion of a drain and source region of said transistor;
prior to selectively modifying said at least one surface characteristic of said first and second device regions, substantially amorphizing a portion of said second device region; and
after selectively modifying said at least one surface characteristic, irradiating said first and second device regions with a beam of said radiation to initiate a dopant activation process in said first and second device regions, wherein each surface portion irradiated by said beam is irradiated for a time interval of approximately 1 microsecond or less.

### Claim 9 (depends on 8)

The method of claim 8, further comprising initiating a second dopant activation process for activating dopants in said first device region.

### Claim 10 (depends on 8)

The method of claim 8, wherein modifying surface characteristics comprises forming a first material layer above said first device region and a second material layer above said second device region, said first material layer having a reduced absorption capability compared to said second material layer with respect to said wavelength range.

### Claim 11 (depends on 10)

The method of claim 10, wherein said specified dopant species is boron.

### Claim 12 (depends on 10)

The method of claim 10, wherein modifying surface characteristics comprises forming a reflective material layer above said first device region.

### Claim 13 (depends on 12)

The method of claim 12, wherein modifying surface characteristics comprises forming a first stressed material layer above said first and second device regions, selectively reducing an absorption capability of said first stressed material layer in said first device region and initiating said dopant activation process in the presence of said stressed material layer.

### Claim 14 (depends on 13)

The method of claim 13, wherein said semiconductor device comprises a third device region and a fourth device region and said method further comprises forming a second stressed material layer above said third and fourth device regions, said second stressed material layer having a different type of stress relative to said first stressed material layer.

### Claim 15

A method, comprising:
preparing a first device region and a second device region of a semiconductor device so as to provide different optical responses in said first and second device regions to radiation of a specified wavelength range;
prior to preparing said first and second device regions so as to provide different optical responses, substantially amorphizing a portion of at least one of said first and second device regions; and
after preparing said first and second device regions so as to provide different optical responses to said radiation of said specified wavelength range, annealing each surface portion of said first and second device regions for a time interval of 1 microsecond or less by at least one of a laser anneal process and a flash anneal process using a beam of said radiation of specified wavelength to initiate at least one of a silicidation process and a dopant activation process in said first and second device regions.

### Claim 16 (depends on 15)

The method of claim 15, wherein said first device region represents a transistor of an SRAM cell.

### Claim 17 (depends on 15)

The method of claim 15, wherein said first device region represents a gate electrode of a transistor and said second device region represents drain and source regions of said transistor.