Semiconductor device and manufacturing method of semiconductor device

Patent metadata

Field	Value
Publication number	US-9123739-B2
Application number	US-201213548078-A
Country	US
Kind code	B2
Filing date	Jul 12, 2012
Priority date	Aug 8, 2011
Publication date	Sep 1, 2015
Grant date	Sep 1, 2015

Abstract

A semiconductor device includes: a first nitride semiconductor layer; a second nitride semiconductor layer formed over the first nitride semiconductor layer; and a gate electrode facing the second nitride semiconductor layer via a gate insulating film. Because the second nitride semiconductor layer is formed by stacking plural semiconductor layers with their Al composition ratios different from each other, the Al composition ratio of the second nitride semiconductor layer changes stepwise. The semiconductor layers forming the second nitride semiconductor layer are polarized in the same direction so that, among the semiconductor layers, a semiconductor layer nearer to the gate electrode has higher (or lower) intensity of polarization. In other words, the intensities of polarization of the semiconductor layers change with an inclination based on their distances from the gate electrode so that, at each interface between two semiconductor layers, the amount of negative charge becomes larger than that of positive charge.

First claim

What is claimed is:

1. A semiconductor device, comprising:
a first nitride semiconductor layer;
a second nitride semiconductor layer formed over the first nitride semiconductor layer;
a gate insulating film contacting the second nitride semiconductor layer; and
a gate electrode facing the second nitride semiconductor layer via the gate insulating film,
wherein the second nitride semiconductor layer is formed by stacking a plurality of semiconductor layers, and the semicond…

Assignees

• Okamoto Yasuhiro
• Nakayama Tatsuo
• Inoue Takashi
• Miyamoto Hironobu
• Renesas Electronics Corp

Inventors

• Okamoto Yasuhiro
• Nakayama Tatsuo
• Inoue Takashi
• Miyamoto Hironobu

Classifications

• H10P14/3416

  Electricity · mapped topic

• H10P14/3216

  Electricity · mapped topic

• H10D62/8503

  Electricity · mapped topic

• H10D64/513 Primary

  Electricity · mapped topic

• H10D64/258

  Electricity · mapped topic