Semiconductor device including insulating films with different thicknesses and method for manufacturing the semiconductor device

• US 10,170,599 B2
• Filed: 05/05/2016
• Issued: 01/01/2019
• Est. Priority Date: 04/13/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Okazaki, Kenichi, Miyamoto, Toshiyuki, Nomura, Masafumi, Hamochi, Takashi, Yamazaki, Shunpei, Sasaki, Toshinari
• Primary Examiner(s): Mazumder, Didarul
• Application Number:
  US15/147,105
• Publication Number:
  US 20160247903A1
• Time in Patent Office: 971 Days
• Field of Search: 257410, 257411, 257 43, 257 64, 438 85, 438 86, 438104, 438754
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02271 deposition by decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition H01L21/02266 takes precedence
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/47573 Etching the layer
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/1259 Multistep manufacturing methods
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

In a semiconductor device including an oxide semiconductor, the amount of oxygen vacancies is reduced. Moreover, electrical characteristics of a semiconductor device including an oxide semiconductor are improved. The semiconductor device includes a transistor including a gate electrode over a substrate, a gate insulating film covering the gate electrode, an oxide semiconductor film overlapping with the gate electrode with the gate insulating film provided therebetween, and a pair of electrodes in contact with the oxide semiconductor film; and over the transistor, a first insulating film covering the gate insulating film, the oxide semiconductor film, and the pair of electrodes; and a second insulating film covering the first insulating film. An etching rate of the first insulating film is lower than or equal to 10 nm/min and lower than an etching rate of the second insulating film when etching is performed at 25° C. with 0.5 weight % of hydrofluoric acid.

Claims

1. A method for manufacturing a semiconductor device, comprising:

forming an oxide semiconductor film over a substrate;

forming a first oxide insulating film over and in contact with the oxide semiconductor film, in an apparatus and by chemical vapor deposition in a first atmosphere, and with a first radio-frequency power supplied to an electrode of the apparatus; and

forming a second oxide insulating film over and in contact with the first oxide insulating film, in the apparatus and by chemical vapor deposition in a second atmosphere, and with a second radio-frequency power supplied to the electrode of the apparatus,

wherein the first radio-frequency power is lower than the second radio-frequency power,

wherein the first oxide insulating film is formed thinner than the second oxide insulating film, and a thickness of the first oxide insulating film is less than or equal to 50 nm, and

wherein spin densities of the first oxide insulating film measured by electron spin resonance are less than or equal to a lower limit of detection at a g-factor of 2.001.

2. The method for manufacturing a semiconductor device according to claim 1,

wherein the first oxide insulating film is formed at a first temperature,

wherein the second oxide insulating film is formed in a second temperature, and

wherein the first temperature is higher than the second temperature.

3. The method for manufacturing a semiconductor device according to claim 1,

wherein an etching rate of the first oxide insulating film is lower than or equal to 10 nm/min and lower than an etching rate of the second oxide insulating film when etching is performed at 25°

C. with a solution of 0.5 weight % of hydrofluoric acid.

4. The method for manufacturing a semiconductor device according to claim 1,

wherein the second oxide insulating film is formed so as to contain oxygen at a higher proportion than a stoichiometric composition.

5. The method for manufacturing a semiconductor device according to claim 1, further comprising stacking a silicon nitride film on the second oxide insulating film.

6. The method for manufacturing a semiconductor device according to claim 1,

wherein a threshold voltage of a transistor including the oxide semiconductor film changes in a positive direction by a bias-temperature stress test,

wherein an amount of change is less than or equal to 3.0V, and

wherein the bias-temperature stress test is performed when a temperature of the substrate is 80°

C., an intensity of an electric field applied to a gate insulating film of the transistor is 1.28 MV/cm, and a performance time is 2000 seconds.

7. A method for manufacturing a semiconductor device, comprising:

forming an oxide semiconductor film over a substrate;

forming a first oxide insulating film over and in contact with the oxide semiconductor film, in an apparatus and by chemical vapor deposition in a first atmosphere, and with a first radio-frequency power supplied to an electrode of the apparatus; and

forming a second oxide insulating film over and in contact with the first oxide insulating film, in the apparatus and by chemical vapor deposition in a second atmosphere, and with a second radio-frequency power supplied to the electrode of the apparatus,

wherein the first radio-frequency power is lower than the second radio-frequency power,

wherein the first oxide insulating film is formed thinner than the second oxide insulating film, and a thickness of the first oxide insulating film is less than or equal to 50 nm,

wherein spin densities of the first oxide insulating film measured by electron spin resonance are less than or equal to a lower limit of detection at a q-factor of 2.001, and

wherein the first oxide insulating film and the second oxide insulating film are a first silicon oxynitride film and a second silicon oxynitride film, respectively.

8. The method for manufacturing a semiconductor device according to claim 7,

wherein the first oxide insulating film is formed at a first temperature,

wherein the second oxide insulating film is formed in a second temperature, and

wherein the first temperature is higher than the second temperature.

9. The method for manufacturing a semiconductor device according to claim 7,

wherein an etching rate of the first oxide insulating film is lower than or equal to 10 nm/min and lower than an etching rate of the second oxide insulating film when etching is performed at 25°

C. with a solution of 0.5 weight % of hydrofluoric acid.

10. The method for manufacturing a semiconductor device according to claim 7,

wherein the second oxide insulating film is formed so as to contain oxygen at a higher proportion than a stoichiometric composition.

11. The method for manufacturing a semiconductor device according to claim 7, further comprising stacking a silicon nitride film on the second oxide insulating film.

12. The method for manufacturing a semiconductor device according to claim 7,

wherein a threshold voltage of a transistor including the oxide semiconductor film changes in a positive direction by a bias-temperature stress test,

wherein an amount of change is less than or equal to 3.0V, and

wherein the bias-temperature stress test is performed when a temperature of the substrate is 80°

C., an intensity of an electric field applied to a gate insulating film of the transistor is 1.28 MV/cm, and a performance time is 2000 seconds.

13. A method for manufacturing a semiconductor device, comprising:

forming an oxide semiconductor film over a substrate;

forming a first oxide insulating film over and in contact with the oxide semiconductor film, in an apparatus and by chemical vapor deposition in a first atmosphere, at a first temperature, and with a first radio-frequency power supplied to an electrode of the apparatus;

forming a second oxide insulating film over and in contact with the first oxide insulating film, in the apparatus and by chemical vapor deposition in a second atmosphere, at a second temperature, and with a second radio-frequency power supplied to the electrode of the apparatus; and

applying a heat treatment to the second oxide insulating film at a third temperature comprised between 250°

C. and 450°

C. in a nitrogen atmosphere, the third temperature being higher than the first temperature and the second temperature,

wherein the first radio-frequency power is lower than the second radio-frequency power,

wherein the first oxide insulating film is formed thinner than the second oxide insulating film, and a thickness of the first oxide insulating film is less than or equal to 50 nm,

wherein spin densities of the first oxide insulating film measured by electron spin resonance are less than or equal to a lower limit of detection at a g-factor of 2.001, and

wherein the first oxide insulating film and the second oxide insulating film are a first silicon oxynitride film and a second silicon oxynitride film, respectively.

14. The method for manufacturing a semiconductor device according to claim 13,

wherein the first temperature is higher than the second temperature.

15. The method for manufacturing a semiconductor device according to claim 13,

wherein an etching rate of the first oxide insulating film is lower than or equal to 10 nm/min and lower than an etching rate of the second oxide insulating film when etching is performed at 25°

C. with a solution of 0.5 weight % of hydrofluoric acid.

16. The method for manufacturing a semiconductor device according to claim 13,

wherein the second oxide insulating film is formed so as to contain oxygen at a higher proportion than a stoichiometric composition.

17. The method for manufacturing a semiconductor device according to claim 13, further comprising stacking a silicon nitride film on the second oxide insulating film.

18. The method for manufacturing a semiconductor device according to claim 13,

wherein a threshold voltage of a transistor including the oxide semiconductor film changes in a positive direction by a bias-temperature stress test,

wherein an amount of change is less than or equal to 3.0V, and

wherein the bias-temperature stress test is performed when a temperature of the substrate is 80°

C., an intensity of an electric field applied to a gate insulating film of the transistor is 1.28 MV/cm, and a performance time is 2000 seconds.