AlGaN HEMT based digital circuits on 3C-SiC(111)/Si(111) pseudosubstrates

Abstract

GaN capped Al 0.2 Ga 0.8 N/AlN/GaN heterostructures were grown on 3C-SiC (111)/Si (111) substrates and used for the implementation of digital circuits. The AlGaN/GaN heterostructure was grown by MOCVD, whereas the 3C-SiC(111)/ Si(111) pseudosubstrate was fabricated using low temperature LPCVD. The SiC layer was 50 nm thick. The presented digital circuits were realised using depletion-mode load and drive high electron mobility transistors. In order to demonstrate the feasibility of digital circuits using standard depletion mode device technology, NAND and NOR digital circuits were designed and fabricated using a standard Au/Ti/ Al/Ti and Au/Ni metallisation scheme for the ohmic and Schottky contacts of the high electron mobility transistors, respectively. The logic function and the voltage transfer characteristics of the fabricated logic circuits are demonstrated and analysed.

AlGaN/GaN High Electron Mobility Transistors Grown by MOVPE on 3C-SiC/Si(111) for RF Applications

“…A current gain cut off frequency (fT) of 176 GHz and a maximum oscillation frequency (fmax) of 70 GHz were obtained on an 80 nm-rectangular gate length device [8]. Furthermore, ft and fmax of 110 GHz were obtained on 100 nm tri-gate devices associated with an ION/IOFF ratio of 10 8 [9]. Beyond these achievements, the thickening of the 3C-SiC intermediate layer seems to be promising to improve the thermal dissipation, to reduce the propagation losses and to increase the RF performance.…”