Bent polysilicon gate structure for small footprint radio frequency (RF) switch

Patent metadata

Field	Value
Publication number	US-10325833-B1
Application number	US-201815900112-A
Country	US
Kind code	B1
Filing date	Feb 20, 2018
Priority date	Feb 20, 2018
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

A semiconductor structure includes a plurality of source/drain regions, a plurality of channel/body regions located between the source/drain regions, and a polysilicon gate structure located over the plurality of channel/body regions. The polysilicon gate structure includes a plurality of polysilicon gate fingers, each extending over a corresponding one of the channel/body regions. Each polysilicon gate finger includes first and second rectangular portions that extend in parallel with a first axis, and a connector portion that introduces an offset between the first and second rectangular portions along the first axis. This offset results in each source/drain region having a first section with a first length, and a second section with a second length, greater than the first length. A single column of contacts are provided in the first section of each source/drain region, and multiple columns of contacts are provided in the second section of each source/drain region.

First claim

The invention claimed is:

1. A semiconductor structure comprising:
an active semiconductor region located on a buried dielectric layer, wherein the active semiconductor region includes a plurality of source/drain regions having a first conductivity type separated by a plurality of channel/body regions having a second conductivity type, wherein each of the source/drain regions includes a first source/drain portion having a first length and a second source/drain portion having a second length, greater than the first length;
a plurality of polysilicon gate fingers, each located over a corresponding one of the plurality of channel/body regions, wherein each polysilicon gate finger includes a first rectangular portion, a second rectangular portion and a connector portion that joins the first and second rectangular portions, wherein the connector portion introduces an offset between the first and second rectangular portions along a first axis, wherein the offset causes the second length to be greater than the first length;
first sets of contacts located over the first source/drain portions, wherein the first sets of contacts provide electrical connections to the first source/drain portions, and wherein each of the first sets of contacts is arranged in a first number of columns along a second axis; and
second sets of contacts located over the second source/drain portions, wherein the first sets of contacts provide electrical connections to the first source/drain portions, and wherein each of the second sets of contacts is arranged in a second number of columns that extend in parallel with the first axis, wherein the second number of columns is greater than the first number of columns.

2. The semiconductor structure of claim 1 , wherein each of the plurality of polysilicon gate fingers is continuous with a polysilicon connector.

3. The semiconductor structure of claim 1 , wherein the first and second rectangular portions of the polysilicon gate fingers are located in parallel with the second axis.

4. The semiconductor structure of claim 1 , wherein the first number is equal to one, and the second number is equal to two.

5. The semiconductor structure of claim 1 , further comprising a metal layer that includes a plurality of metal traces, wherein each metal trace contacts a corresponding one of the first set of contacts and a corresponding one of the second set of contacts.

6. The semiconductor structure of claim 5 , wherein each metal trace is wider over the corresponding one of the second set of contacts than over the corresponding one of the first set of contacts.

7. The semiconductor structure of claim 1 , wherein the active semiconductor region is rectangular.

8. The semiconductor structure of claim 1 , wherein each of the first rectangular portions of the polysilicon gate fingers has the same size as each of the second rectangular portions of the polysilicon gate fingers over the active semiconductor region.

9. The semiconductor structure of claim 1 , wherein the first source/drain portion of each source/drain region is adjacent to the second source/drain portion of an adjacent source/drain region across a corresponding one of the plurality of channel/body regions.

10. The semiconductor structure of claim 1 , wherein each of the first sets of contacts is located adjacent to corresponding ones of the second sets of contacts across the polysilicon gate fingers.

11. A semiconductor structure comprising:
an active semiconductor region located on a buried dielectric layer, wherein the active semiconductor region includes:
a first source/drain region including a first source/drain portion having a first length and a continuous second source/drain portion having a second length, greater than the first length,
a second source/drain region including a third source/drain portion having a third length and a continuous fourth source/drain portion having a fourth length, greater than the third length, and
a channel/body region located between the first and second source/drain regions, wherein the first source/drain portion and the fourth source/drain portion are adjacent across the channel/body region, and the second source/drain portion and the third source/drain portion are adjacent across the channel/body region;

a gate electrode located over the channel/body region;
a first plurality of contacts located over the first source/drain portion, wherein the first plurality of contacts provide electrical connections to the first source/drain portion, and wherein the first plurality of contacts are arranged in a first number of columns;
a second plurality of contacts located over the second source/drain portion, wherein the second plurality of contacts provide electrical connections to the second source/drain portion, and wherein the second plurality of contacts are arranged in a second number of columns, greater than the first number of columns;
a third plurality of contacts located over the third source/drain portion, wherein the third plurality of contacts provide electrical connections to the third source/drain portion, and wherein the third plurality of contacts are arranged in a third number of columns; and
a fourth plurality of contacts located over the fourth source/drain portion, wherein the fourth plurality of contacts provide electrical connections to the fourth source/drain portion, and wherein the fourth plurality of contacts are arranged in a fourth number of columns, greater than the third number of columns.

12. The semiconductor structure of claim 11 , wherein the polysilicon gate finger includes a first rectangular portion, a second rectangular portion and a connector portion that joins the first and second rectangular portions, wherein the connector portion introduces an offset between the first and second rectangular portions.

13. The semiconductor structure of claim 11 , wherein the first number and the third number are equal to one, and the second number and the fourth number are equal to two.

14. The semiconductor structure of claim 11 , further comprising a first metal trace that connects the first and second plurality of contacts, and a second metal trace that connects the third and fourth plurality of contacts.

15. The semiconductor structure of claim 14 , wherein the first metal trace is wider over the second plurality of contacts than over the first plurality of contacts, and the second metal trace is wider over the fourth plurality of contacts than the third plurality of contacts.

16. A silicon on insulator (SOI) transistor structure comprising:
an active semiconductor region located on a buried dielectric layer, wherein the active semiconductor region includes a plurality of source/drain regions having a first conductivity type separated by channel/body regions having a second conductivity type; and
a plurality of polysilicon gate fingers, each extending over a corresponding one of the channel/body regions, and each including a first rectangular portion, a second rectangular portion and a connecting portion that joins the first and second rectangular portions, wherein the first rectangular portions extend in parallel with a first axis and are separated by a first spacing, and wherein the second rectangular portions extend in parallel with the first axis and are separated by a second spacing, greater than the first spacing, and wherein each connecting portion introduces an offset between the corresponding first and second rectangular portions along a second axis, wherein the offset results in the source/drain regions having a plurality of different lengths along the second axis.

Assignees

• Newport Fab Llc

Inventors

• Kanawati Roda
• Hurwitz Paul D
• Chaudhry Samir

Classifications

• H10W44/20

  at high-frequency [HF] or radio frequency [RF] · CPC title

• H10W20/484 Primary

  Interconnections having extended contours, e.g. pads having mesh shape or interconnections comprising connected parallel stripes · CPC title

• H01L23/4824 Primary

  Electricity · mapped topic

• H01L27/0207

  Electricity · mapped topic

• H01L27/1203

  Electricity · mapped topic