Method and system for doping control in gallium nitride based devices

A method of manufacturing a vertical JFET, the method comprising:

• providing a GaN-based substrate having a surface and a first electrical contact opposing the surface;
• forming a GaN-based drift layer coupled to the GaN-based substrate and operable to conduct current in a direction substantially orthogonal to the surface, wherein forming the GaN-based drift layer comprises doping the drift layer with indium to cause the indium concentration of the drift layer to be less than about 1×1016 cm−3 and to cause the carbon concentration of the drift layer to be less than about 1×1016 cm−3;
• forming an n-type channel layer coupled to the GaN-based drift layer;
• forming an n-contact layer coupled to the GaN-based drift layer and substantially parallel to the surface;
• forming a second electrical contact electrically coupled to the n-contact layer;
• forming a p-type gate region electrically coupled to the n-type channel layer;
• and
• forming a third electrical contact electrically coupled to the p-type gate region.