Semiconductor device and method for manufacturing the same

• US 10,290,745 B2
• Filed: 06/26/2017
• Issued: 05/14/2019
• Est. Priority Date: 12/10/2014
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Tanaka, Tetsuhiro, Shimomura, Akihisa, Yamane, Yasumasa, Tokumaru, Ryo, Sato, Yuhei, Tsutsui, Kazuhiro
• Primary Examiner(s): Nguyen, Niki H
• Application Number:
  US15/632,764
• Publication Number:
  US 20170294542A1
• Time in Patent Office: 687 Days
• Field of Search: 257223, 257227, 257291, 257292, 257439, 257655, 257E211, 257E27125, 257E27112, 257E29117, 257E29145, 257E29147, 257E29151, 257E29182, 257E29202, 438149, 438157, 438128, 438154, 438282
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: H01L 2029/42388 characterised by the shape of the insulating material
• CPC Class Codes: H01L 21/02266 deposition by physical ablation of a target, e.g. sputtering, reactive sputtering, physical vapour deposition or pulsed laser deposition
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 27/1207 combined with devices in contact with the semiconductor body, i.e. bulk/SOI hybrid circuits
• 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 29/42384 for thin film field effect transistors, e.g. characterised by the thickness or the shape of the insulator or the dimensions, the shape or the lay-out of the conductor
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/513 the variation being perpendicular to the channel plane
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• 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 29/78648 arranged on opposing sides of the channel
• 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

A transistor with stable electrical characteristics is provided. The transistor includes a first insulator over a substrate; first to third oxide insulators over the first insulator; a second insulator over the third oxide insulator; a first conductor over the second insulator; and a third insulator over the first conductor. An energy level of a conduction band minimum of each of the first and second oxide insulators is closer to a vacuum level than that of the oxide semiconductor is. An energy level of a conduction band minimum of the third oxide insulator is closer to the vacuum level than that of the second oxide insulator is. The first insulator contains oxygen. The number of oxygen molecules released from the first insulator measured by thermal desorption spectroscopy is greater than or equal to 1E14 molecules/cm² and less than or equal to 1E16 molecules/cm².

Claims

1. A semiconductor device comprising:

a first insulator over a substrate;

a first oxide insulator comprising indium over the first insulator;

an oxide semiconductor comprising indium in contact with the first oxide insulator;

a second oxide insulator comprising indium in contact with the oxide semiconductor;

a pair of conductors in contact with the second oxide insulator;

a third oxide insulator comprising at least one element other than oxygen included in the second oxide insulator in contact with the second oxide insulator and the pair of conductors;

a second insulator over the third oxide insulator;

a first conductor over the second insulator; and

a third insulator over the first conductor,

wherein a region in the second oxide insulator between the pair of conductors has a smaller thickness than regions in the second oxide insulator overlapping with the pair of conductors,

wherein an energy level of a conduction band minimum of each of the first oxide insulator and the second oxide insulator is closer to a vacuum level than an energy level of a conduction band minimum of the oxide semiconductor is,

wherein an energy level of a conduction band minimum of the third oxide insulator is closer to the vacuum level than the energy level of the conduction band minimum of the second oxide insulator is.

2. The semiconductor device according to claim 1,

wherein part of the first conductor does not overlap with the pair of conductors.

3. The semiconductor device according to claim 1,

wherein the third oxide insulator comprises an element M (titanium, gallium, yttrium, zirconium, lanthanum, cerium, neodymium, tin, or hafnium), zinc, and oxygen.

4. The semiconductor device according to claim 1,

wherein the pair of conductors each have a stacked-layer structure, and

wherein an upper layer of each of the pair of conductors comprises one or more kinds of elements selected from silver, copper, ruthenium, iridium, platinum, and gold.

5. The semiconductor device according to claim 1, further comprising:

a fourth conductor; and

a fourth insulator,

wherein the fourth conductor is formed over the substrate and below the first insulator,

wherein the fourth insulator is formed between the fourth conductor and the first insulator, and

wherein the fourth insulator is an oxide or a nitride comprising boron, aluminum, silicon, scandium, titanium, gallium, yttrium, zirconium, indium, lanthanum, cerium, neodymium, hafnium, or thallium.

6. The semiconductor device according to claim 1,

wherein the first oxide insulator, the oxide semiconductor, and the second oxide insulator each further comprise an element M (titanium, gallium, yttrium, zirconium, lanthanum, cerium, neodymium, tin, or hafnium), zinc, and oxygen.

7. The semiconductor device according to claim 1,

wherein the third insulator comprises oxygen and aluminum.

8. A semiconductor device comprising:

a first insulator over a substrate;

a first oxide insulator comprising indium over the first insulator;

an oxide semiconductor comprising indium in contact with the first oxide insulator;

a second oxide insulator comprising indium in contact with the oxide semiconductor;

a pair of conductors in contact with the second oxide insulator;

a third oxide insulator comprising at least one element other than oxygen included in the second oxide insulator in contact with the second oxide insulator and the pair of conductors;

a second insulator over the third oxide insulator;

a first conductor over the second insulator; and

a third insulator over the first conductor,

wherein a region in the second oxide insulator between the pair of conductors has a smaller thickness than regions in the second oxide insulator overlapping with the pair of conductors,

wherein an energy gap of each of the first oxide insulator and the second oxide insulator is larger than an energy gap of the oxide semiconductor,

wherein an energy gap of the third oxide insulator is larger than the energy gap of the second oxide insulator.

9. The semiconductor device according to claim 8,

wherein part of the first conductor does not overlap with the pair of conductors.

10. The semiconductor device according to claim 8,

wherein the third oxide insulator comprises an element M (titanium, gallium, yttrium, zirconium, lanthanum, cerium, neodymium, tin, or hafnium), zinc, and oxygen.

11. The semiconductor device according to claim 8,

wherein the pair of conductors each have a stacked-layer structure, and

wherein an upper layer of each of the pair of conductors comprises one or more kinds of elements selected from silver, copper, ruthenium, iridium, platinum, and gold.

12. The semiconductor device according to claim 8, further comprising:

a fourth conductor; and

a fourth insulator,

wherein the fourth conductor is forming over the substrate and below the first insulator,

wherein the fourth insulator is formed between the fourth conductor and the first insulator, and

wherein the fourth insulator is an oxide or a nitride comprising boron, aluminum, silicon, scandium, titanium, gallium, yttrium, zirconium, indium, lanthanum, cerium, neodymium, hafnium, or thallium.

13. The semiconductor device according to claim 8,

wherein the first oxide insulator, the oxide semiconductor, and the second oxide insulator each further comprise an element M (titanium, gallium, yttrium, zirconium, lanthanum, cerium, neodymium, tin, or hafnium), zinc, and oxygen.

14. The semiconductor device according to claim 8,

wherein the third insulator comprises oxygen and aluminum.