Memory semiconductor device having aligned side surfaces

• US 8,884,283 B2
• Filed: 05/27/2011
• Issued: 11/11/2014
• Est. Priority Date: 06/04/2010
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kato, Kiyoshi
• Primary Examiner(s): Ingham, John C
• Application Number:
  US13/117,603
• Publication Number:
  US 20110297939A1
• Time in Patent Office: 1,264 Days
• Field of Search: 257/43, 257/72, 257/E29.296, 438/104
• US Class Current: 257/43
• CPC Class Codes: G11C 16/0433 comprising cells containing a single floating gate transistor and one or more separate select transistors
• CPC Class Codes: G11C 16/26 Sensing or reading circuits; Data output circuits
• 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 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 29/7869 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
• CPC Class Codes: H10B 41/00 Electrically erasable-and-programmable ROM [EEPROM] devices comprising floating gates

Abstract

An object is to provide a semiconductor device having a novel structure with a high degree of integration. A semiconductor device includes a semiconductor layer having a channel formation region, a source electrode and a drain electrode electrically connected to the channel formation region, a gate electrode overlapping with the channel formation region, and a gate insulating layer between the channel formation region and the gate electrode. A portion of a side surface of the gate insulating layer and a portion of a side surface of the source electrode or the drain electrode are substantially aligned with each other when seen from a planar direction.

Claims

1. A semiconductor device comprising:

a semiconductor layer comprising a channel formation region;

a source electrode and a drain electrode over the semiconductor layer and electrically connected to the channel formation region;

a gate electrode over the channel formation region;

a gate insulating layer between the semiconductor layer and the gate electrode; and

an electrode over the gate insulating layer, the electrode overlapping with the source electrode or the drain electrode with the gate insulating layer interposed therebetween,

wherein an upper surface of the source electrode and an upper surface of the drain electrode are covered with the gate insulating layer,

wherein the source electrode and the drain electrode comprise at least one of a metal, a metal oxide and a metal nitride,

wherein a side surface of the semiconductor layer is in contact with the source electrode and the drain electrode, and

wherein a portion of a side surface of the gate insulating layer and a portion of a side surface of the source electrode or the drain electrode are substantially aligned with each other.

2. The semiconductor device according to claim 1, wherein a portion of a side surface of the semiconductor layer and the portion of the side surface of the source electrode or the drain electrode are substantially aligned with each other.

3. The semiconductor device according to claim 1, wherein a width of the semiconductor layer and a width of the source electrode or the drain electrode are substantially aligned with each other.

4. The semiconductor device according to claim 1, wherein the channel formation region comprises an oxide semiconductor.

5. The semiconductor device according to claim 1, wherein a material of the gate insulating layer and a material of the source electrode or the drain electrode are processable by the same process.

6. The semiconductor device according to claim 1, wherein the portion of the side surface of the gate insulating layer is perpendicular to a channel length direction.

7. A semiconductor device comprising:

an impurity region provided in a semiconductor substrate; and

a first transistor and a second transistor, each of the first transistor and the second transistor comprising;

a channel formation region provided in the semiconductor substrate;

a gate insulating layer over the channel formation region;

a gate electrode over the gate insulating layer, the gate electrode overlapping with the channel formation region; and

a source region and a drain region provided in the semiconductor substrate and between which the channel formation region is sandwiched,

wherein one of the source region and the drain region is covered by the gate insulating layer while the gate insulating layer is not provided over the other of the source region and the drain region,

wherein each of the first transistor and the second transistor includes a portion of the impurity region as the other of the source region and the drain region, and

wherein a portion of a side surface of the channel formation region and a portion of a side surface of the gate insulating layer are substantially aligned with each other.

8. The semiconductor device according to claim 7, wherein the portion of the side surface of the gate insulating layer and a portion of a side surface of the gate electrode are substantially aligned with each other.

9. The semiconductor device according to claim 7, wherein a width of the channel formation region and a width of the gate insulating layer are substantially aligned with each other.

10. The semiconductor device according to claim 7, wherein a width of the channel formation region, a width of the gate insulating layer and a width of the gate electrode are substantially aligned with each other.

11. The semiconductor device according to claim 7, wherein a material of the channel formation region, a material of the gate insulating layer and a material of the gate electrode are processable by the same process.

12. A semiconductor device comprising:

a first transistor comprising;

a first channel formation region provided in a semiconductor substrate;

a first gate insulating layer over the first channel formation region;

a first gate electrode over the first gate insulating layer, the first gate electrode overlapping with the first channel formation region; and

a source region and a drain region provided in the semiconductor substrate and between which the first channel formation region is sandwiched; and

a second transistor comprising;

a semiconductor layer comprising a second channel formation region;

a source electrode and a drain electrode electrically connected to the second channel formation region;

a second gate electrode over the second channel formation region; and

a second gate insulating layer between the second channel formation region and the second gate electrode,

wherein an upper surface of the source electrode and an upper surface of the drain electrode are covered with the second gate insulating layer,

wherein the first gate electrode is in direct contact with the source electrode or the drain electrode,

wherein the source electrode and the drain electrode comprise at least one of a metal, a metal oxide and a metal nitride,

wherein a side surface of the semiconductor layer is in contact with the source electrode and the drain electrode,

wherein the first channel formation region and the second channel formation region comprise different semiconductor materials as respective main components, and

wherein a portion of a side surface of the second gate insulating layer and a portion of a side surface of the source electrode or the drain electrode are substantially aligned with each other.

13. The semiconductor device according to claim 12, wherein a portion of a side surface of the semiconductor layer and the portion of the side surface of the source electrode or the drain electrode are substantially aligned with each other.

14. The semiconductor device according to claim 12, further comprising an electrode over the second gate insulating layer, the electrode overlapping with the source electrode or the drain electrode with the second gate insulating layer interposed therebetween,

wherein a portion of a side surface of the electrode and the portion of the side surface of the second gate insulating layer are substantially aligned with each other.

15. The semiconductor device according to claim 12, wherein a width of the semiconductor layer and a width of the source electrode or the drain electrode are substantially aligned with each other.

16. The semiconductor device according to claim 12, wherein the second channel formation region comprises an oxide semiconductor.

17. The semiconductor device according to claim 12, wherein a material of the first channel formation region, a material of the first gate insulating layer and a material of the first gate electrode are processable by the same process.

18. The semiconductor device according to claim 12, wherein a material of the second gate insulating layer and a material of the source electrode or the drain electrode are processable by the same process.

19. The semiconductor device according to claim 12, wherein the portion of the side surface of the second gate insulating layer is perpendicular to a channel length direction.

20. The semiconductor device according to claim 12, further comprising a plurality of first transistors and a plurality of second transistors,

wherein a source region or a drain region of one of the plurality of first transistors is electrically connected to a drain region or a source region of a first transistor adjacent to the one of the plurality of first transistors, and

wherein a source electrode or a drain electrode of one of the plurality of second transistors is electrically connected to a drain electrode or a source electrode of a second transistor adjacent to the one of the plurality of second transistors.