UNSTRAINED InAlN/GaN HEMT STRUCTURE

摘要

InAlN has been investigated as barrier layer material for GaN-HEMT structures, potentially offering higher sheet charge densities and higher breakdown fields. Lattice matched growth of the barrier layer can be achieved with 17 % In content, avoiding piezo polarization. In this configuration the sheet charge density is only induced by spontaneous polarization. First experimental results of unpassivated undoped samples realized on 111-Si substrate exceed a DC output current density of 1.8 A/mm for a gate length of 0.5μm. Small signal measurements yield a f_t = 26 GHz and f_(max) = 14 GHz, still limited by the residual conductivity of the Si-substrate. A saturated output power at 2 GHz in class A bias point yielded a density of 4.1 W/mm at V_(DS) = 24 V.