# US 10,371,571 B2 · Thin film structure for micro-bolometer and method for fabricating the same

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- Number: US 10,371,571 B2
- Document ID: US10371571B2
- Status: Granted
- Kind: B2
- Application number: 15/926,366
- Filed: 2018-03-20
- Published: 2018-11-22
- Granted: 2019-08-06
- Earliest claimed: 2017-05-19
- Assignees: Korea Institute of Science and Technology; Unist (Ulsan National Institute of Science and Technology)
- Applicants: Korea Institute of Science and Technology; Unist(Ulsan National Institute of Science and Technology)
- Inventors: Seung Hyub Baek; Tae Hyeon Kil; Sanghyeon Kim; Won Jun Choi; Jeong Min Baik; Ki-Suk Lee
- Web page: https://patentgrep.com/patent/US10371571B2

## CPC

- G01J 1/42: using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10)
- G01J 5/024: {Special manufacturing steps or sacrificial layers or layer structures}
- G01J 5/046: {Materials; Selection of thermal materials}
- G01J 5/20: using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
- H10P 14/6938: {the material containing at least one metal element, e.g. metal oxides, metal oxynitrides or metal oxycarbides}
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Disclosed is a resistor thin film for micro-bolometer for growth of a vanadium dioxide (VO2) thin film in tetragonal VO2 crystal phase by deposition of VO2 on oxide with perovskite structure and a method for fabricating the same, and the resistor thin film for micro-bolometer according to the present disclosure includes a silicon substrate, an oxide thin film with perovskite structure formed on the silicon substrate, and a VO2 thin film in tetragonal crystal phase formed on the oxide thin film with perovskite structure.

## Claims

### Claim 1

A resistor thin film for micro-bolometer, comprising:
a semiconductor substrate;
an oxide thin film with perovskite structure formed on the semiconductor substrate; and
a vanadium dioxide (VO2) thin film in tetragonal crystal phase formed on the oxide thin film with perovskite structure.

### Claim 2 (depends on 1)

The resistor thin film for micro-bolometer according to claim 1, wherein the semiconductor substrate is one of a silicon substrate, a GaAs substrate, and a sapphire substrate, and
when the semiconductor substrate is a silicon substrate, a silicon oxide film is provided on the silicon substrate, and the oxide thin film with perovskite structure is formed on the silicon oxide film.

### Claim 3 (depends on 1)

The resistor thin film for micro-bolometer according to claim 1, wherein the vanadium dioxide (VO2) thin film in tetragonal crystal phase is formed with a thickness of 40 to 100 nm.

### Claim 4 (depends on 1)

The resistor thin film for micro-bolometer according to claim 1, wherein the oxide thin film with perovskite structure is formed with a thickness of 5 to 20 nm.

### Claim 5 (depends on 1)

The resistor thin film for micro-bolometer according to claim 1, wherein the oxide thin film with perovskite structure is made of one of CaTiO3, LaAlO3, BaTiO3, SrTiO3, SrRuO3 and BiFeO3.

### Claim 6 (depends on 1)

The resistor thin film for micro-bolometer according to claim 1, wherein the vanadium dioxide (VO2) thin film in tetragonal crystal phase has a temperature coefficient of resistance (TCR) absolute value of 3%/K or more and a specific resistance value of 1 Ωcm or less.

### Claim 7

A method for fabricating a resistor thin film for micro-bolometer, comprising:
preparing a semiconductor substrate;
stacking an oxide thin film with perovskite structure on the semiconductor substrate; and
forming a vanadium dioxide (VO2) thin film in tetragonal crystal phase on the oxide thin film with perovskite structure.

### Claim 8 (depends on 7)

The method for fabricating a resistor thin film for micro-bolometer according to claim 7, wherein in the forming of a vanadium dioxide (VO2) thin film in tetragonal crystal phase on the oxide thin film with perovskite structure,
during deposition of vanadium dioxide (VO2), tetragonal VO2 crystal phase similar to a lattice structure of the oxide with perovskite structure has a preferred orientation among various crystal phases of vanadium dioxide (VO2).

### Claim 9 (depends on 7)

The method for fabricating a resistor thin film for micro-bolometer according to claim 7, wherein the forming of a vanadium dioxide (VO2) thin film in tetragonal crystal phase on the oxide thin film with perovskite structure uses a sputtering process in which a sputtering target is vanadium dioxide (VOx) in monoclinic crystal phase, a process pressure is set to 5 to 20 mTorr, a process temperature is set to 200 to 500° C., and mixed gas of O2 and Ar is supplied into a sputtering chamber at a ratio of O2/(Ar+O2)=0.2 to 0.3%.

### Claim 10 (depends on 7)

The method for fabricating a resistor thin film for micro-bolometer according to claim 7, wherein the forming of a vanadium dioxide (VO2) thin film in tetragonal crystal phase on the oxide thin film with perovskite structure uses a reactive sputtering process in which a sputtering target is vanadium metal and reactive gas including O2 is supplied into a chamber.

### Claim 11 (depends on 7)

The method for fabricating a resistor thin film for micro-bolometer according to claim 7, wherein the oxide thin film with perovskite structure is made of one of CaTiO3, LaAlO3, BaTiO3, SrTiO3, SrRuO3, and BiFeO3.

### Claim 12 (depends on 7)

The method for fabricating a resistor thin film for micro-bolometer according to claim 7, wherein the vanadium dioxide (VO2) thin film in tetragonal crystal phase is formed with a thickness of 40 to 100 nm, and the oxide thin film with perovskite structure is formed with a thickness of 5 to 20 nm.

### Claim 13 (depends on 7)

The method for fabricating a resistor thin film for micro-bolometer according to claim 7, wherein the vanadium dioxide (VO2) thin film in tetragonal crystal phase has a temperature coefficient of resistance (TCR) absolute value of 3%/K or more and a specific resistance value of 11 Ωcm or less.

### Claim 14 (depends on 7)

The method for fabricating a resistor thin film for micro-bolometer according to claim 7, wherein the semiconductor substrate is one of a silicon substrate, a GaAs substrate and a sapphire substrate, and
when the semiconductor substrate is a silicon substrate, a silicon oxide film is provided on the silicon substrate, and the oxide thin film with perovskite structure is formed on the silicon oxide film.

### Claim 15 (depends on 7)

The method for fabricating a resistor thin film for micro-bolometer according to claim 7, wherein the stacking an oxide thin film with perovskite structure on the semiconductor substrate is performed at room temperature.