Structure for Making a Top-side Contact to a Substrate

• US 20090194812A1
• Filed: 01/26/2009
• Published: 08/06/2009
• Est. Priority Date: 03/30/2007
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Chun-Tai Wu, Ihsiu Ho
• Inventors: Ho, Ihsiu, Wu, Chun-Tai
• Granted Patent: US 7,989,884 B2
• Time in Patent Office: Days
• 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

1-48. -48. (canceled)

49. A semiconductor structure comprising:

a starting semiconductor substrate having a 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 a 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.

50. The semiconductor structure of claim 49 wherein the starting semiconductor substrate comprises silicon.

51. The semiconductor structure of claim 49 wherein the recessed portion is substantially filled with an epitaxial layer.

52. The semiconductor structure of claim 49 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.

53. The semiconductor structure of claim 49 wherein the semiconductor material has a different conductivity type than the starting semiconductor substrate.

54. The semiconductor structure of claim 49 wherein the semiconductor material has a different conductivity type than the starting semiconductor substrate.

55. The semiconductor structure of claim 49 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.

56. A semiconductor structure, comprising:

a starting semiconductor substrate having a 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 a 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.

57. The semiconductor device of claim 56 wherein the starting semiconductor substrate comprises silicon.

58. The semiconductor device of claim 56 wherein the dielectric spacer comprises oxide.

59. The semiconductor device of claim 56 wherein the recessed portion is substantially filled with an epitaxial layer.

60. The semiconductor device of claim 56 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.

61. The semiconductor device of claim 56 wherein the semiconductor material has the same conductivity type than the starting semiconductor substrate.

62. The semiconductor device of claim 56 wherein the semiconductor material has a different conductivity type than the starting semiconductor substrate.

63. The semiconductor device of claim 56 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.