Static induction semiconductor device with a distributed main electrode structure and static induction semiconductor device with a static induction main electrode shorted structure

• US 5,418,376 A
• Filed: 02/28/1994
• Issued: 05/23/1995
• Est. Priority Date: 03/02/1993
• Status: Expired due to Term

• Current Assignee: NGK Insulators Limited
• Original Assignee: Toyo Denki Seizo Kabushiki Kaisha
• Inventors: Shimizu, Naohiro, Tamamushi, Takashige, Muraoka, Kimihiro
• Primary Examiner(s): WOJCIECHOWICZ, EDWARD JOSEPH
• Application Number:
  US08/202,821
• Time in Patent Office: 449 Days
• Field of Search: 257/136, 257/264, 257/498, 257/260, 257/475, 257/281
• US Class Current: 257/136
• CPC Class Codes: H01L 29/7392 with PN junction gate, e.g. field controlled thyristors (FCTh), static induction thyristors (SITh)

Abstract

The present invention is to provide a static induction semiconductor device with a distributed main electrode structure and a static induction semiconductor device with a static induction main electrode shorted structure where the main electrode region is composed of regions of higher and lower impurity densities relative to each other and formed partly in contact with the lower impurity density region as well, and alternatively a static induction short-circuit region opposite in conductivity type to the main electrode region is formed in the lower impurity density region surrounded by the higher impurity density region.

Claims

1. A static induction semiconductor device with a distributed main electrode structure, which has a first main electrode region formed in a first main surface of a high resistivity layer, a second main electrode region formed in the first or second main surface of said high resistivity layer, and a control region formed near said first main electrode region and in which said control region forms a channel region in said high resistivity layer and controls the height of a potential barrier in said channel region to control a main current between said first main electrode region and said second main electrode region, characterized in that said first main electrode region has a structure wherein regions of higher and lower impurity densities relative to each other are distributed and that a main electrode formed in contact with said first main electrode region is partly in contact with said lower impurity density region as well as said higher impurity density region, and said higher and lower impurity density regions in said first main electrode region are the same in conductivity type but opposite to said control region.

2. The static induction semiconductor device of claim 1, characterized in that said main electrode formed in contact with said first main electrode region makes ohmic contact with said higher impurity density region and non-ohmic or Schottky contact with said lower impurity density region.

3. The static induction semiconductor device of claim 1, characterized in that said main electrode in contact with said first main electrode region is formed of aluminum (Al), molybdenum (Mo), tungsten (W), platinum (Pt), titanium (Ti), nickel (Ni) or their silicon (Si)-base alloys or silicides.

4. The static induction semiconductor device of claim 1, characterized in that said higher impurity density region in said first main electrode region is composed of separated regions.

5. The static induction semiconductor device of claim 1, characterized in that said control region has a buried structure.

6. The static induction semiconductor device of claim 1, characterized in that said control region has a recessed structure.

7. The static induction semiconductor device of claim 1, characterized in that said control region has a planar structure.

8. The static induction semiconductor device of claim 1 is a static induction thyristor.

9. The static induction semiconductor device of claim 1 is a static induction transistor.

10. A static induction semiconductor device with a static induction main electrode shorted structure, which has a first main electrode region formed in a first main surface of a high resistivity layer, a second main electrode region formed in said first or second main surface of said high resistivity layer, and a control region formed near said first main electrode region and which said control region forms a channel region in said high resistivity layer and controls the height of a potential barrier in said channel region to control a main current between said first main electrode region and said second main electrode region, characterized in that said first main electrode region has a structure wherein regions of higher and lower impurity densities relative to each other and a short-circuit region respectively formed in said lower impurity density region surrounded by said higher impurity density regions are distributed, that a main electrode formed in contact with said first main electrode region is partly in contact with said lower impurity density region and said short-circuit region as well as said higher impurity density region, that said short-circuit region is of the same conductivity type as said control region but is opposite to said higher impurity density region and that a potential barrier is formed in said lower impurity region between said short-circuit region and said control region by a depletion layer spreading from said higher impurity density region into said lower impurity density region, and said higher and lower impurity density regions are of the same conductivity type but opposite to said control region.

11. The static induction semiconductor device of claim 10, characterized in that said main electrode formed in contact with said first main electrode structure makes ohmic contact with said higher impurity density region and non-ohmic or Schottky contact with said lower impurity density region.

12. The static induction semiconductor device of claim 10, characterized in that said main electrode in contact with said first main electrode region is formed of aluminum (Al), molybdenum (Mo), tungsten (W), platinum (Pt), titanium (Ti), nickel (Ni) or their silicon (Si)-base alloys or silicides.

13. The static induction semiconductor device of claim 10, characterized in that said higher impurity density region in said first main electrode region is composed of separated regions.

14. The static induction semiconductor device of claim 10, characterized in that said control region has a buried structure.

15. The static induction semiconductor device of claim 10, characterized in that said control region has a recessed structure.

16. The static induction semiconductor device of claim 10, characterized in that said control region has a planar structure.

17. The static induction semiconductor device of claim 10 is a static induction thyristor.

18. The static induction semiconductor device of claim 10 is a static induction transistor.

19. A static induction semi-conductor device in accordance with claim 10, wherein:

said short circuit region has a depth into said high resistivity layer which is less than a depth of said higher impurity density region into said high resistivity layer.

20. A static induction semiconductor device comprising:

a high resistivity layer with a first and second main surface;

a first main electrode region formed in said first main surface of said high resistivity layer;

a second main electrode region formed in said second main surface of said high resistivity layer;

a control region formed adjacent said first main electrode region and said control region forming a channel region in said high resistivity layer and controlling a height of a potential barrier in said channel region to control a main current between said first main electrode region and said second main electrode region;

a high and low density region formed in said first main electrode region, said high density region having an impurity density higher than said low density region;

a short-circuit region formed in said low density region and surrounded by said high density region, said short-circuit region being of a same conductivity type as said control region and opposite to said high density region to form a potential barrier in said low region between said short-circuit region and said control region by a depletion layer spreading from said high density region into said low density region, said high and low density regions being of a same conductivity type and opposite to said control region, said short circuit region having a depth into said high resistivity layer less than a depth of said high density region into said high resistivity layer;

a main electrode formed in contact with said first main electrode region and partly in contact with said low density region, said short-circuit region and said high density region.