Vertical GaN-based semiconductor device

摘要

A vertical semiconductor device in which pinch-off characteristics and breakdown voltage characteristics can be stably improved by fixing the electric potential of a p-type GaN barrier layer with certainty is provided. The semiconductor device includes a GaN-based stacked layer having an opening, a regrown layer including a channel located so as to cover a wall surface of the opening, an n+-type source layer that is in ohmic contact with the source electrode, a p-type GaN barrier layer, and a p+-type GaN-based supplementary layer located between the p-type GaN barrier layer and the n+-type source layer. The p+-type GaN-based supplementary layer and the n+-type source layer form a tunnel junction to fix the electric potential of the p-type GaN barrier layer at a source potential.

主权项

1. A vertical semiconductor device including a GaN-based stacked layer having an opening, the semiconductor device comprising:
a regrown layer including a channel located so as to cover a wall surface of the opening; a p-type GaN-based semiconductor layer having an end face covered with the regrown layer at the wall surface of the opening; an n+-type GaN-based semiconductor layer serving as a top layer of the GaN-based stacked layer; a p+-type GaN-based supplementary layer containing a p-type impurity in a concentration higher than that of the p-type GaN-based semiconductor layer, the p+-type GaN-based supplementary layer being located between the p-type GaN-based semiconductor layer and the n+-type GaN-based semiconductor layer; a gate electrode located on the regrown layer in the opening; and a source electrode located on the GaN-based stacked layer around the opening so as to be in contact with the regrown layer and the n+-type GaN-based semiconductor layer, wherein the regrown layer includes an electron drift layer and an electron source layer and the channel is formed of two-dimensional electron gas generated in the electron drift layer at a position near an interface between the electron drift layer and the electron source layer, and the p+-type GaN-based supplementary layer is included in a structure that electrically connects the p-type GaN-based semiconductor layer and the source electrode to each other in order to fix an electric potential of the p-type GaN-based semiconductor layer at an electric potential of the source electrode, and the n+-type GaN-based semiconductor layer and the p+-type GaN-based supplementary layer form a tunnel junction, and the source electrode and the p-type GaN-based semiconductor layer are electrically connected to each other through the tunnel junction.