Improved AlGaN/GaN HEMTs using Fe doping

This work reports on using Fe modulation doped GaN to fabricate AlGaN/GaN HEMTs to avoid high dislocation density and conductive GaN buffer layers, limiting device performance. Structural characterization of these layers consisted on HRXRD, PL measurements, obtaining information about polarization fields, strain and charge densities. Moreover, Schottky diodes and U-shaped transistors were fabricated at ISOM with 1.3 and 0.3 μm gate lengths. Maximum saturation currents and transconductances were above 1.2 A/mm and 290 mS/mm, respectively. Moreover, the effect of a AlN spacer led to higher electron density and mobility that in reference samples with higher Al content.