Semiconductor device

• US 8,847,220 B2
• Filed: 07/06/2012
• Issued: 09/30/2014
• Est. Priority Date: 07/15/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Mandala, Michelle
• Application Number:
  US13/543,109
• Publication Number:
  US 20130015437A1
• Time in Patent Office: 816 Days
• Field of Search: 257/43, 257/107, 257/E29.068
• US Class Current: 257/43
• 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

A semiconductor device including an oxide semiconductor can have stable electric characteristics and high reliability. A transistor in which an oxide semiconductor layer containing indium, titanium, and zinc is used as a channel formation region and a semiconductor device including the transistor are provided. As a buffer layer in contact with the oxide semiconductor layer, a metal oxide layer containing an oxide of one or more elements selected from titanium, aluminum, gallium, zirconium, hafnium, and a rare earth element can be used.

Claims

1. A semiconductor device comprising:

a metal oxide layer;

an oxide semiconductor layer containing indium, titanium, and zinc, the oxide semiconductor layer being provided over the metal oxide layer;

a first electrode and a second electrode over the oxide semiconductor layer and the metal oxide layer,

a gate insulating film over and in contact with the oxide semiconductor layer, the first electrode and the second electrode; and

a gate electrode layer over the gate insulating film.

2. The semiconductor device according to claim 1,

wherein the metal oxide layer contains an oxide of at least one element selected from titanium, aluminum, gallium, zirconium, hafnium, and a rare earth element.

3. The semiconductor device according to claim 1,

wherein the oxide semiconductor layer at least partly includes a region containing oxygen in excess of a stoichiometric ratio in a crystalline state.

4. The semiconductor device according to claim 1,

wherein the oxide semiconductor layer is a crystalline semiconductor layer.

5. The semiconductor device according to claim 1,

wherein the oxide semiconductor layer includes low-resistance regions,

wherein the low-resistance regions sandwich a channel formation region overlapping with the gate electrode layer, and

wherein the low-resistance regions include one or more selected from phosphorus (P), arsenic (As), antimony (Sb), boron (B), aluminum (Al), nitrogen (N), argon (Ar), helium (He), neon (Ne), indium (In), fluorine (F), chlorine (Cl), titanium (Ti), and zinc (Zn).

6. A semiconductor device comprising:

a first metal oxide layer;

an oxide semiconductor layer containing indium, titanium, and zinc, the oxide semiconductor layer being provided over the first metal oxide layer;

a second metal oxide layer provided over the oxide semiconductor layer so as to cover a side surface of the oxide semiconductor layer;

a gate insulating film over the second metal oxide layer;

a gate electrode layer over the gate insulating film;

an insulating film over the gate electrode layer, the insulating film having openings; and

a source electrode layer and a drain electrode layer provided over the insulating film to be electrically connected to the oxide semiconductor layer through the openings.

7. The semiconductor device according to claim 6,

wherein the first metal oxide layer contains an oxide of at least one element selected from titanium, aluminum, gallium, zirconium, hafnium, and a rare earth element, and

wherein the second metal oxide layer contains an oxide of at least one element selected from titanium, aluminum, gallium, zirconium, hafnium, and a rare earth element.

8. The semiconductor device according to claim 6,

wherein the oxide semiconductor layer at least partly includes a region containing oxygen in excess of a stoichiometric ratio in a crystalline state.

9. The semiconductor device according to claim 6,

wherein the oxide semiconductor layer is a crystalline semiconductor layer.

10. The semiconductor device according to claim 6,

wherein the oxide semiconductor layer includes low-resistance regions, and

wherein the low-resistance regions sandwich a channel formation region overlapping with the gate electrode layer, and

wherein the low-resistance regions include one or more selected from phosphorus (P), arsenic (As), antimony (Sb), boron (B), aluminum (Al), nitrogen (N), argon (Ar), helium (He), neon (Ne), indium (In), fluorine (F), chlorine (Cl), titanium (Ti), and zinc (Zn).

11. A semiconductor device comprising:

a first metal oxide layer;

an oxide semiconductor layer containing indium, titanium, and zinc, the oxide semiconductor layer being provided over the first metal oxide layer;

a second metal oxide layer provided over the oxide semiconductor layer so as to cover a side surface of the first metal oxide layer and a side surface of the oxide semiconductor layer;

a gate insulating film over the second metal oxide layer;

a gate electrode layer over the gate insulating film;

an insulating film over the gate electrode layer, the insulating film having openings; and

a source electrode layer and a drain electrode layer provided over the insulating film to be electrically connected to the oxide semiconductor layer through the openings.

12. The semiconductor device according to claim 11,

wherein the first metal oxide layer contains an oxide of at least one element selected from titanium, aluminum, gallium, zirconium, hafnium, and a rare earth element, and

wherein the second metal oxide layer contains an oxide of at least one element selected from titanium, aluminum, gallium, zirconium, hafnium, and a rare earth element.

13. The semiconductor device according to claim 11,

wherein the oxide semiconductor layer at least partly includes a region containing oxygen in excess of a stoichiometric ratio in a crystalline state.

14. The semiconductor device according to claim 11,

wherein the oxide semiconductor layer is a crystalline semiconductor layer.

15. The semiconductor device according to claim 11,

wherein the oxide semiconductor layer includes low-resistance regions, and

wherein the low-resistance regions sandwich a channel formation region overlapping with the gate electrode layer, and

wherein the low-resistance regions include one or more selected from phosphorus (P), arsenic (As), antimony (Sb), boron (B), aluminum (Al), nitrogen (N), argon (Ar), helium (He), neon (Ne), indium (In), fluorine (F), chlorine (Cl), titanium (Ti), and zinc (Zn).