Semiconductor device

摘要

A semiconductor device includes a buffer layer, a channel layer and a barrier layer formed over a substrate, a trench penetrating through the barrier layer to reach the middle of the channel layer, and a gate electrode disposed inside the trench via a gate insulating film. The channel layer contains n-type impurities, and a region of the channel layer positioned on a buffer layer side has an n-type impurity concentration larger than a region of the channel layer positioned on a barrier layer side, and the buffer layer is made of nitride semiconductor having a band gap wider than that of the channel layer. The channel layer is made of GaN and the buffer layer is made of AlGaN. The channel layer has a channel lower layer containing n-type impurities at an intermediate concentration and a main channel layer formed thereon and containing n-type impurities at a low concentration.

主权项

1. A semiconductor device comprising:
a first nitride semiconductor layer formed over a substrate; a second nitride semiconductor layer formed on the first nitride semiconductor layer; a third nitride semiconductor layer formed on the second nitride semiconductor layer and made of nitride semiconductor having a band gap wider than that of the second nitride semiconductor layer; a trench penetrating through the third nitride semiconductor layer to reach a middle of the second nitride semiconductor layer; and a gate electrode disposed inside the trench via a gate insulating film, wherein the second nitride semiconductor layer contains n-type impurities, a region of the second nitride semiconductor layer positioned on a first nitride semiconductor layer side has a concentration of the n-type impurities larger than a region of the second nitride semiconductor layer positioned on a third nitride semiconductor layer side, and the first nitride semiconductor layer is made of nitride semiconductor having a band gap wider than that of the second nitride semiconductor layer or nitride semiconductor containing p-type impurities.