Backgating, high-current and breakdown characterisation of AlGaN/GaN HEMTs on silicon substrates

The backgating effect, as well as breakdown and high-current performance, of AlGaN/GaN HEMTs on silicon substrates are studied. The material structure of the investigated devices differs in the thickness of the stress-relaxing intermediate layer sequence (/spl sim/1 /spl mu/m and /spl sim/2.5 /spl mu/m thick). It is shown that the transistor backgating effect is reduced for the thicker sequence. Similarly, the reverse gate current is two orders of magnitude lower and the gate-drain breakdown voltage increases substantially in devices with the thicker sequence. An increase from /spl sim/40 V to /spl sim/160 V of the HEMT blocking capability, measured under electrostatic discharge-like conditions, is also observed.