Crystallographic and electric properties of MOVPE-grown AlGaN/GaN-based FETs on Si(0 0 1) substrates

We present AlGaN/GaN-based FETs on Si(0 0 1) grown by metalorganic vapor phase epitaxy (MOVPE). The influence of the substrate off-orientation on the crystallographic quality is investigated by spatially resolved electron backscatter diffraction. A stringent correlation of the surface morphology of GaN layers grown on differently misoriented Si(0 0 1) with two different in-plane alignments of adjacent GaN crystallites is observed. On a 2.5 μm thick single-crystalline and crack-free GaN-based buffer layer structure, an AlGaN/GaN FET heterostructure was realized. A drain–source current of 245 mA/mm with a transconductance of 90 mS/mm was achieved.