# US 7,609,144 B2 · High resistivity thin film composition and fabrication method

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 7,609,144 B2
- Document ID: US7609144B2
- Status: Granted
- Kind: B2
- Application number: 11/608,668
- Filed: 2006-12-08
- Published: 2008-06-12
- Granted: 2009-10-27
- Earliest claimed: 2006-12-08
- Assignees: Analog Devices, Inc.
- Inventors: Michael Lee; Steven Wright; Philip Judge; Craig Wilson; Gregory Cestra; Derek Bowers
- Web page: https://patentgrep.com/patent/US7609144B2

## CPC

- H01C 7/006: {Thin film resistors}
- Y10T 29/49082: Resistor making
- H01C: RESISTORS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A thin film composition is made from silicon, an insulator such as alumina or silicon dioxide, and at least one additional material such as chromium, nickel, boron and/or carbon. These materials are combined to provide a thin film having a ρ of at least 0.02 Ω-cm (typically 0.02-1.0 Ω-cm), and a TCR of less than ±1000 ppm/° C. (typically less than ±300 ppm/° C.). A sheet resistance of at least 20 kΩ/□ may also be obtained. The resulting thin film is preferably at least 200 thick, to reduce surface scattering conduction currents.

## Claims

### Claim 1

A high resistivity thin film, comprising:
silicon; and
an insulator comprising alumina (Al2O3), silicon dioxide (SiO2), or both; and
at least one additional material, said additional materials selected from a group consisting of chromium, nickel, boron and/or carbon, said silicon, insulator and additional materials combined to form a thin film having a resistivity (ρ) of at least 0.02 Ω-cm and a temperature coefficient of resistance (TCR) of less than ±300 ppm/° C.

### Claim 2 (depends on 1)

The thin film of claim 1, wherein said thin film has a sheet resistance of at least 5 kΩ/□.

### Claim 3 (depends on 1)

The thin film of claim 1, wherein said thin film has a sheet resistance of at least 20 kΩ/□.

### Claim 4 (depends on 1)

The thin film of claim 1, wherein said thin film is laser-trimmable.

### Claim 5 (depends on 1)

The thin film of claim 1, wherein said thin film is at least 200 thick.

### Claim 6 (depends on 1)

The thin film of claim 1, wherein said film is annealed after being deposited on a substrate.

### Claim 7

A high resistivity thin film, comprising:
silicon;
an insulator comprising alumina (Al2O3), silicon dioxide (SiO2), or both; and
at least one additional material, said additional materials selected from a group consisting of chromium, nickel, boron and/or carbon, said silicon, insulator and additional materials combined to form a thin film having a resistivity (ρ) of 0.02-1.0 Ω-cm, a temperature coefficient of resistance (TCR) less than ±300 ppm/° C., and a sheet resistance of at least 5 kΩ/□.

### Claim 8

A method of forming a high resistivity thin film, comprising:
providing an insulator comprising alumina (Al2O3), silicon dioxide (SiO2), or both;
providing silicon;
providing at least one additional material, said additional materials selected from a group consisting of chromium, nickel, boron and/or carbon;
combining said insulator, silicon and additional materials to form a thin film;
said providing and combining carried out such that said thin film has a resistivity (ρ) of at least 0.02 Ω-cm and a temperature coefficient of resistance (TCR) less than ±1000 ppm/° C.

### Claim 9 (depends on 8)

The method of claim 8, further comprising:
depositing said thin film on a substrate; and
annealing said thin film.

### Claim 10 (depends on 9)

The method of claim 9, further comprising laser-trimming said deposited and annealed thin film.

### Claim 11 (depends on 9)

The method of claim 9, wherein said deposited and annealed thin film is at least 200 thick.

### Claim 12 (depends on 8)

The method of claim 8, wherein said thin film is formed by sputtering, the target material for said sputtering comprising said insulator, said silicon, and said at least one additional material.

### Claim 13 (depends on 12)

The method of claim 12, wherein said target material comprises said insulator, silicon, nickel and chromium.

### Claim 14 (depends on 12)

The method of claim 12, wherein said target material comprises said insulator, silicon, chromium, boron and carbon.

### Claim 15

A method of forming a high resistivity thin film, comprising:
providing an insulator comprising alumina (Al2O3), silicon dioxide (SiO2), or both;
providing silicon;
providing at least one additional material, said additional materials selected from a group consisting of chromium, nickel, boron and/or carbon;
combining said insulator, silicon and additional materials to form a thin film;
depositing said thin film;
annealing said deposited thin film;
said providing, combining, depositing and annealing being carried out such that said deposited and annealed thin film has a resistivity (ρ) of at least 0.02 Ω-cm and a temperature coefficient of resistance (TCR) less than ±1000 ppm/° C.

### Claim 16 (depends on 15)

The method of claim 15, further comprising incorporating oxygen into said thin film during said depositing step.