III-V semiconductor devices with buried contacts

A method of manufacturing a semiconductor device, comprising:

• forming a first region of III-V semiconductor material on a semiconductor substrate;
• forming a second region of III-V semiconductor material on the first region so that the second region is spaced apart from the semiconductor substrate by the first region, the second region being of a different composition than the first region;
• forming a buried contact extending from the semiconductor substrate to the second region through the first region, the buried contact electrically connecting the second region to the semiconductor substrate, wherein the buried contact has a first side contacting the semiconductor substrate and a second opposing side contacting the second region;
• and
• forming a dielectric material extending from the second side of the buried contact toward a side of the second region facing away from the first region.