Thin film structure for micro-bolometer and method for fabricating the same

Patent metadata

Field	Value
Publication number	US-2018335341-A1
Application number	US-201815926366-A
Country	US
Kind code	A1
Filing date	Mar 20, 2018
Priority date	May 19, 2017
Publication date	Nov 22, 2018
Grant date	—

Abstract

Disclosed is a resistor thin film for micro-bolometer for growth of a vanadium dioxide (VO 2 ) thin film in tetragonal VO 2 crystal phase by deposition of VO 2 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 VO 2 thin film in tetragonal crystal phase formed on the oxide thin film with perovskite structure.

First claim

What is claimed is:

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 (VO 2 ) thin film in tetragonal crystal phase formed on the oxide thin film with perovskite structure.

2 . 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.

3 . The resistor thin film for micro-bolometer according to claim 1 , wherein the vanadium dioxide (VO 2 ) thin film in tetragonal crystal phase is formed with a thickness of 40 to 100 nm.

4 . 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.

5 . The resistor thin film for micro-bolometer according to claim 1 , wherein the oxide thin film with perovskite structure is made of one of CaTiO 3 , LaAlO 3 , BaTiO 3 , SrTiO 3 , SrRuO 3 and BiFeO 3 .

6 . The resistor thin film for micro-bolometer according to claim 1 , wherein the vanadium dioxide (VO 2 ) 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.

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 (VO 2 ) thin film in tetragonal crystal phase on the oxide thin film with perovskite structure.

8 . The method for fabricating a resistor thin film for micro-bolometer according to claim 7 , wherein in the forming of a vanadium dioxide (VO 2 ) thin film in tetragonal crystal phase on the oxide thin film with perovskite structure,
during deposition of vanadium dioxide (VO 2 ), tetragonal VO 2 crystal phase similar to a lattice structure of the oxide with perovskite structure has a preferred orientation among various crystal phases of vanadium dioxide (VO 2 ).

9 . The method for fabricating a resistor thin film for micro-bolometer according to claim 7 , wherein the forming of a vanadium dioxide (VO 2 ) 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 (VO x ) 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 O 2 and Ar is supplied into a sputtering chamber at a ratio of O 2 /(Ar+O 2 )=0.2 to 0.3%.

10 . The method for fabricating a resistor thin film for micro-bolometer according to claim 7 , wherein the forming of a vanadium dioxide (VO 2 ) 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 O 2 is supplied into a chamber.

11 . 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 CaTiO 3 , LaAlO 3 , BaTiO 3 , SrTiO 3 , SrRuO 3 , and BiFeO 3 .

12 . The method for fabricating a resistor thin film for micro-bolometer according to claim 7 , wherein the vanadium dioxide (VO 2 ) 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.

13 . The method for fabricating a resistor thin film for micro-bolometer according to claim 7 , wherein the vanadium dioxide (VO 2 ) 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.

14 . 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.

15 . 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.

Assignees

• Korea Inst Sci & Tech
• Ulsan Nat Inst Science & Tech Unist

Inventors

• Baek Seung Hyub
• Kil Tae Hyeon
• Kim Sanghyeon
• Choi Won Jun
• Baik Jeong Min
• Lee Ki-Suk

Classifications

• H10P14/6938

  the material containing at least one metal element, e.g. metal oxides, metal oxynitrides or metal oxycarbides · CPC title

• G01J5/046

  Materials; Selection of thermal materials · CPC title

• G01J5/20

  using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices · CPC title

• G01J5/024 Primary

  Special manufacturing steps or sacrificial layers or layer structures · CPC title

• G01J1/42 Primary

  using electric radiation detectors (optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10) · CPC title