Cascode semiconductor device structure and method therefor

A method of forming a semiconductor device comprising:

• providing a substrate structure comprising:
• a semiconductor substrate having a first major surface and an opposing second major surface;
• a heterostructure disposed over the first major surface, the heterostructure comprising:
• a group III-V channel layer;
• and
• a group III-V barrier layer over the group III-V channel layer;
• providing a first electrode disposed proximate to a first portion of the group III-V channel layer;
• providing a second electrode disposed proximate to a second portion of the group III-V channel layer and spaced apart from the first electrode;
• providing a control electrode disposed between the first electrode and the second electrode;
• providing a third electrode disposed adjacent to the second major surface of the semiconductor substrate;
• providing a rectifier device as part of the semiconductor substrate;
• and
• providing a fourth electrode electrically coupled to the first electrode and the rectifier device, wherein:
• the rectifier device is electrically decoupled from the second electrode;
• and
• the control electrode is electrically connected to the third electrode through the semiconductor substrate to provide the semiconductor device as a two terminal device.

A method of forming a semiconductor device comprising:

• providing a semiconductor substrate having a first major surface and an opposing second major surface;
• providing a rectifier device disposed in the semiconductor substrate;
• providing a heterostructure adjacent the first major surface, the heterostructure comprising:
• a channel layer;
• and
• a barrier layer over the channel layer;
• providing a first electrode disposed proximate to a first portion of the channel layer;
• providing a second electrode disposed proximate to a second portion of the channel layer and spaced apart from the first electrode;
• providing a control electrode disposed proximate to the channel layer and between the first electrode and the second electrode and configured to control a first current path between the first electrode and the second electrode;
• providing a first trench electrode extending through the heterostructure into the semiconductor substrate and electrically connected to the first electrode;
• and
• providing a third electrode disposed on the second major surface of the semiconductor substrate, wherein:
• the rectifier device is electrically connected to the first trench electrode and electrically connected to the third electrode, but not electrically connected to the second electrode,
• the rectifier device is configured to provide a second current path generally perpendicular to the first current path, and
• the control electrode is electrically coupled to the third electrode through the semiconductor substrate to provide the semiconductor device as a two-terminal device.