Semiconductor device

• US 9,899,535 B2
• Filed: 10/13/2016
• Issued: 02/20/2018
• Est. Priority Date: 12/27/2013
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Tanaka, Tetsuhiro, Suzawa, Hideomi, Yamane, Yasumasa, Sato, Yuhei, Tezuka, Sachiaki
• Primary Examiner(s): TAYLOR, EARL N
• Application Number:
  US15/292,287
• Publication Number:
  US 20170033230A1
• Time in Patent Office: 495 Days
• Field of Search: 257 43
• CPC Class Codes: H01L 27/0688 Integrated circuits having a three-dimensional layout
• CPC Class Codes: H01L 27/088 the components being field-effect transistors with insulated gate
• CPC Class Codes: H01L 27/0886 including transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• 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 29/16 including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

To provide a transistor with stable electrical characteristics, a transistor with a low off-state current, a transistor with a high on-state current, a semiconductor device including the transistor, or a durable semiconductor device. The semiconductor device includes a first transistor using silicon, an aluminum oxide film over the first transistor, and a second transistor using an oxide semiconductor over the aluminum oxide film. The oxide semiconductor has a lower hydrogen concentration than silicon.

Claims

1. A semiconductor device comprising:

a first transistor comprising silicon;

a first aluminum oxide film over the first transistor;

a second transistor comprising an oxide semiconductor over the first aluminum oxide film; and

a second aluminum oxide film over the second transistor,

wherein the oxide semiconductor has a lower hydrogen concentration than the silicon, and

wherein the first aluminum oxide film includes a first region with a density of lower than 3.2 g/cm³.

2. The semiconductor device according to claim 1, wherein the density of the first region included in the first aluminum oxide film is measured by an X-ray reflectivity method.

3. The semiconductor device according to claim 1,

wherein the first aluminum oxide film includes a second region with a density of higher than 3.2 g/cm³, and

wherein a percentage of the first region is higher than a percentage of the second region in the first aluminum oxide film.

4. The semiconductor device according to claim 1,

wherein the second transistor comprises a conductor over and in contact with the first aluminum oxide film.

5. The semiconductor device according to claim 1, wherein a concentration of hydrogen in the oxide semiconductor is lower than or equal to 1×

10¹⁹ atoms/cm³.

6. The semiconductor device according to claim 1, further comprising a silicon oxide film between the first aluminum oxide film and the second transistor,

wherein a number of oxygen atoms per unit volume is more than twice a number of silicon atoms per unit volume in the silicon oxide film.

7. The semiconductor device according to claim 1, wherein the first aluminum oxide film is capable of blocking oxygen and hydrogen.

8. A semiconductor device comprising:

a first transistor comprising silicon;

a first aluminum oxide film over the first transistor;

a second transistor over the first aluminum oxide film, the second transistor comprising;

a first conductor over the first aluminum oxide film;

a first insulator over the first conductor;

a first oxide semiconductor over the first insulator;

a second oxide semiconductor over the first oxide semiconductor;

a second conductor and a third conductor over the second oxide semiconductor;

a third oxide semiconductor over the second conductor and the third conductor;

a second insulator over the third conductor;

a fourth conductor over the third conductor, and

a second aluminum oxide film over the second transistor,

wherein each of the first oxide semiconductor, the second oxide semiconductor, and the third oxide semiconductor has a lower hydrogen concentration than the silicon, and

wherein the first aluminum oxide film includes a first region with a density of lower than 3.2 g/cm³.

9. The semiconductor device according to claim 8, wherein the density of the first region included in the first aluminum oxide film is measured by an X-ray reflectivity method.

10. The semiconductor device according to claim 8,

wherein the first aluminum oxide film includes a second region with a density of higher than 3.2 g/cm³, and

wherein a percentage of the first region is higher than a percentage of the second region in the first aluminum oxide film.

11. The semiconductor device according to claim 8, wherein the first conductor is in contact with the first aluminum oxide film.

12. The semiconductor device according to claim 8, wherein a concentration of hydrogen in the second oxide semiconductor is lower than or equal to 1×

10¹⁹ atoms/cm³.

13. The semiconductor device according to claim 8, further comprising a silicon oxide film between the first aluminum oxide film and the second transistor,

wherein a number of oxygen atoms per unit volume is more than twice a number of silicon atoms per unit volume in the silicon oxide film.

14. The semiconductor device according to claim 8, wherein the first aluminum oxide film is capable of blocking oxygen and hydrogen.