Wide bandgap semiconductor device and method for manufacturing the same

A wide bandgap semiconductor device made of wide bandgap semiconductor material for controlling current flowing from source means to drain means by gate means, comprising:

• drift means for transporting carriers by drift field between the source means and drain means;
• body means disposed in the drift means for storing the carriers to be injected into the drift means;
• source means disposed in the body means for providing the carriers so that the carriers can serve as the current flowing from the source means to the drain means;
• channel means disposed at the top surface of the body means neighboring to the source means and further disposed at the top surface of the drift means for providing a current path between the source means and drain means;
• and
• gate means directly contact with the top surface of the channel means so that an edge of gate means reaches to the source means, for controlling potential in the channel means, and simultaneously for achieving electrical isolation between the gate means and source means.

A method for manufacturing a wide bandgap semiconductor device, comprising:

• forming a drift layer of a first conductivity type made of a wide bandgap semiconductor material on a base material made of the wide bandgap semiconductor material;
• forming a body region of a second conductivity type opposite to the first conductivity type made of the wide bandgap semiconductor material at the top surface of and in the drift layer;
• forming a source region of the first conductivity type made of the wide bandgap semiconductor material at the top surface of and in the body region;
• forming a channel layer of the first conductivity type made of the wide bandgap semiconductor material at the top surface of and in the body region neighboring to the source region and further at the top surface of and in the drift layer;
• depositing a semiconductor layer having a different bandgap energy from that of the wide bandgap semiconductor material directly on the channel layer;
• and
• doping impurity atoms from the top surface of the semiconductor layer.

A method for manufacturing a wide bandgap semiconductor device, comprising:

• forming a drift layer of a first conductivity type made of a wide bandgap semiconductor material on a base material made of the wide bandgap semiconductor material;
• forming a body region of a second conductivity type opposite to the first conductivity type made of the wide bandgap semiconductor material at the top surface of and in the drift layer;
• forming a channel layer of the first conductivity type made of the wide bandgap semiconductor material at the top surface of and in the body region neighboring to the source region and further at the top surface of and in the drift layer;
• and
• depositing a semiconductor layer having a different bandgap energy from that of the wide bandgap semiconductor material directly on the channel layer;
• delineating the semiconductor layer so as to form a window portion, exposing a portion of the body region, and to form a pattern of a gate electrode;
• and
• doping the first conductivity type impurity atoms from the top surface of the semiconductor layer so as not dope the bottom portion of the semiconductor layer, and simultaneously doping the portion of the body region exposed in the window portion, thereby simultaneously forming the gate electrode directly contacting with the top surface of the channel layer and a source region of the first conductivity type at the top surface of and in the body region.