GaN-based compound semiconductor device

A GaN-based compound semiconductor device comprising:

• a plurality of semiconductor layers formed to constitute an insulated gate structure, said semiconductor layers including:
• a first semiconductor layer made of a GaN-based semiconductor having a low impurity concentration;
• a second semiconductor layer made of a GaN-based semiconductor having a conductivity opposite to that of said first semiconductor layer and a high impurity concentration, said second semiconductor layer being embedded in said first semiconductor layer;
• a third semiconductor layer made of a GaN-based semiconductor having the same conductivity as that of said first semiconductor layer and a high impurity concentration, said third semiconductor layer being embedded in said second semiconductor layer to comprise a source region and to define the length of a channel region formed in said second semiconductor layer;
• and
• a fourth semiconductor layer made of a GaN-based semiconductor having the same conductivity as that of said first semiconductor layer and a high impurity concentration, said fourth semiconductor layer spaced apart from said second semiconductor layer, or said fourth semiconductor layer being located on a surface of said first semiconductor layer to form a drain region.

A GaN-based compound semiconductor device, comprising:

• a first semiconductor layer made of a GaN-based compound having a first conductivity;
• a second semiconductor layer made of a GaN-based compound having a second conductivity, said first and second semiconductor layers forming a p-n junction;
• a third semiconductor layer made of a GaN-based compound having said first conductivity, said third semiconductor layer being embedded in said second semiconductor layer;
• an insulating film formed on part of a surface of said third semiconductor layer;
• and
• a gate electrode formed on said insulating film.

The GaN-based compound semiconductor device, comprising:

• a first semiconductor layer made of a GaN-based semiconductor having a low impurity concentration;
• a second semiconductor layer made of a GaN-based semiconductor having a conductivity opposite to that of said first semiconductor layer and a high impurity concentration, said second semiconductor layer being embedded in said first semiconductor layer;
• a third semiconductor layer made of a GaN-based semiconductor having the same conductivity as that of said first semiconductor layer and a high impurity concentration, said third semiconductor layer being embedded in said second semiconductor layer to form a source region and to define the length of a channel region formed in said second semiconductor layer, said third and second semiconductor layers forming a p-n junction diode;
• and
• a fourth semiconductor layer made of a GaN-based semiconductor having the same conductivity as that of said first semiconductor layer and a high impurity concentration, said fourth semiconductor layer being embedded in said first semiconductor layer and separated from said second semiconductor layer by a groove formed in said first semiconductor layer to form a drain region.