Structure for making a top-side contact to a substrate

• US 7,989,884 B2
• Filed: 01/26/2009
• Issued: 08/02/2011
• Est. Priority Date: 03/30/2007
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Semiconductor Corporation (ON Semiconductor Corporation)
• Inventors: Wu, Chun-Tai, Ho, Ihsiu
• Primary Examiner(s): Smith, Bradley K
• Assistant Examiner(s): Karimy, Mohammad
• Application Number:
  US12/359,670
• Publication Number:
  US 20090194812A1
• Time in Patent Office: 918 Days
• Field of Search: 257/330, 257/E29.262
• US Class Current: 257/330
• CPC Class Codes: H01L 21/743 Making of internal connections, substrate contacts
• CPC Class Codes: H01L 29/0653 adjoining the input or output region of a field-effect device, e.g. the source or drain region
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/66712 Vertical DMOS transistors, i.e. VDMOS transistors
• CPC Class Codes: H01L 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT
• CPC Class Codes: H01L 29/7809 having both source and drain contacts on the same surface, i.e. Up-Drain VDMOS transistors
• CPC Class Codes: H01L 29/872 Schottky diodes
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A semiconductor structure includes a starting semiconductor substrate having a recessed portion. A semiconductor material is formed in the recessed portion, and has a higher resistivity than the starting semiconductor substrate. A body region extends in the semiconductor material, and has a conductivity type opposite that of the semiconductor material. Source regions extend in the body region, and have a conductivity type opposite that of the body region. A gate electrode extends adjacent to but is insulated from the body region. A first interconnect layer extends over and is in contact with a non-recessed portion of the starting semiconductor substrate. The first interconnect layer and the non-recessed portion provide a top-side electrical contact to portions of the starting semiconductor substrate underlying the semiconductor material.

Claims

1. A semiconductor structure comprising:

a starting semiconductor substrate having a recessed portion and a non-recessed portion;

a semiconductor material in the recessed portion, the semiconductor material having a higher resistivity than the starting semiconductor substrate;

a body region extending in the semiconductor material, the body region and the semiconductor material being of opposite conductivity type;

source regions in the body region, the source and body regions being of opposite conductivity type;

a gate electrode extending adjacent to but being insulated from the body region; and

a first interconnect layer extending over and in contact with the non-recessed portion of the starting semiconductor substrate, the first interconnect layer and the non-recessed portion providing a top-side electrical contact to portions of the starting semiconductor substrate underlying the semiconductor material.

2. The semiconductor structure of claim 1 wherein the starting semiconductor substrate comprises silicon.

3. The semiconductor structure of claim 1 wherein the recessed portion is substantially filled with an epitaxial layer.

4. The semiconductor structure of claim 1 wherein the starting semiconductor substrate is characterized by a resistivity in the rang of 5-7 mOhm-cm, and the semiconductor material is characterized by a resistivity in the range of 0.2 to 0.4 Ohm-cm.

5. The semiconductor structure of claim 1 wherein the semiconductor material has the same conductivity type as the starting semiconductor substrate.

6. The semiconductor structure of claim 1 wherein the semiconductor material has a different conductivity type than the starting semiconductor substrate.

7. The semiconductor structure of claim 1 wherein the vertically conducting device further comprises:

a heavy body region in the body region; and

a second interconnect layer electrically contacting the source regions and the heavy body region, the second interconnect layer being insulated from the first interconnect layer.

8. A semiconductor structure, comprising:

a starting semiconductor substrate having a recessed portion and a non-recessed portion;

a semiconductor material in the recessed portion, the semiconductor material having a higher resistivity than the starting semiconductor substrate;

a dielectric spacer vertically extending between the semiconductor material and the non-recessed portion of the starting semiconductor substrate;

a body region extending in the semiconductor material, the body region and the semiconductor material being of opposite conductivity type;

source regions in the body region, the source and body regions being of opposite conductivity type;

a gate electrode extending adjacent to but being insulated from the body region; and

a first interconnect layer extending over and in contact with the non-recessed portion of the starting semiconductor substrate, the first interconnect layer and the non-recessed portion providing a top-side electrical contact to portions of the starting semiconductor substrate underlying the semiconductor material.

9. The semiconductor device of claim 8 wherein the starting semiconductor substrate comprises silicon.

10. The semiconductor device of claim 8 wherein the dielectric spacer comprises oxide.

11. The semiconductor device of claim 8 wherein the recessed portion is substantially filled with an epitaxial layer.

12. The semiconductor device of claim 8 wherein the starting semiconductor substrate is characterized by a resistivity in the range of 5 to 7 mOhm-cm, and the semiconductor material is characterized by a resistivity in the range of 0.2 to 0.4 Ohm-cm.

13. The semiconductor device of claim 8 wherein the semiconductor material has the same conductivity type than the starting semiconductor substrate.

14. The semiconductor device of claim 8 wherein the semiconductor material has a different conductivity type than the starting semiconductor substrate.

15. The semiconductor device of claim 8 wherein the vertically conducting device further comprises:

a heavy body region in the body region; and

a second interconnect layer electrically contacting the source regions and the heavy body region, the second interconnect layer being insulated from the first interconnect layer.