Abstract
Herein, the interest of cubic silicon carbide as a template for the growth of AlGaN/ GaN high electron mobility transistor (HEMT) heterostructures on silicon substrates for high-frequency operation is shown. On the one hand, 0.6-0.8 μm-thick 3C-SiC grown by chemical vapor deposition on intrinsic silicon substrate having initial resistivity superior to 5 kΩ cm enables the metalorganic vapor phase epitaxy of GaN buffer layers with propagation losses below 0.4 dB mm À1 at 40 GHz and 0.5 dB mm À1 at 67 GHz. On the other hand, an HEMT heterostructure is grown on 1.5 μm-thick 3C-SiC on 4 off-axis silicon substrate having an initial resistivity superior to 200 Ω cm that allows to keep a sufficiently resistive epilayer stack limiting the loss up to 0.78 dB mm À1 at 40 GHz. Device process developed on a piece of the 100 mm diameter wafer leads to the demonstration of DC transistor operation with low leakage currents. Compared with direct growth on silicon, these templates enable reduced radio frequency (RF) propagation losses that are very interesting for high-frequency transistors and circuits operation.