Semiconductor device and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-11222972-B2
Application number	US-202016825525-A
Country	US
Kind code	B2
Filing date	Mar 20, 2020
Priority date	Mar 29, 2019
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

A semiconductor device includes a semiconductor substrate, a trench provided in the semiconductor substrate, a trench gate formed in the trench, a vertical transistor having the trench gate, an active region having the vertical transistor, a field region surrounding the active region and having a protection diode, and a field insulating film formed on a surface of the semiconductor substrate, the protection diode being formed on the field insulating film. The trench gate includes a first polysilicon layer and has an embedded part embedded in the trench and an extension part connected to the embedded part and extending onto the surface of the semiconductor substrate, the protection diode includes a second polysilicon layer thicker than the first polysilicon layer, and an overlapping part having the second polysilicon layer is formed on the extension part.

First claim

What is claimed is:

1. A semiconductor device, comprising:
a semiconductor substrate;
a trench provided in the semiconductor substrate;
a trench gate formed in the trench;
a vertical transistor having the trench gate;
an active region having the vertical transistor;
a field region surrounding the active region and having a protection diode; and
a field insulating film formed on a surface of the semiconductor substrate, the protection diode being formed on the field insulating film,
wherein the trench gate comprises a first polysilicon layer and has an embedded part embedded in the trench and an extension part connected to the embedded part and extending onto the surface of the semiconductor substrate,
wherein the protection diode comprises a second polysilicon layer thicker than the first polysilicon layer, and
wherein an overlapping part having the second polysilicon layer is formed on the extension part.

2. The semiconductor device according to claim 1 , further comprising:
an insulating film formed on the vertical transistor and the protection diode;
a first gate contact formed in the insulating film on the overlapping part;
a second gate contact formed in the insulating film on one end of the protection diode; and
a metal wiring electrically connecting the trench gate and the one end of the protection diode through the first gate contact and the second gate contact.

3. The semiconductor device according to claim 2 , further comprising:
a first source contact formed in the insulating film on a source of the vertical transistor;
a second source contact formed in the insulating film on another end of the protection diode; and
a metal wiring electrically connecting the source and the other end of the protection diode through the first source contact and the second source contact.

4. The semiconductor device according to claim 1 , wherein the width of the trench is not more than 0.2 μm.

Assignees

• Ablic Inc

Inventors

• Yoshimura Mitsuhiro

Classifications

• H10D64/252

  for vertical or pseudo-vertical devices · CPC title

• H10D62/103

  for increasing or controlling the breakdown voltage of reverse-biased devices · CPC title

• H10D30/668 Primary

  having trench gate electrodes, e.g. UMOS transistors · CPC title

• H10D30/0297

  using recessing of the gate electrodes, e.g. to form trench gate electrodes · CPC title

• H10D8/00

  Diodes (variable-capacitance diodes H10D1/64; gated diodes H10D12/00) · CPC title