High electron mobility AlInGaN/AlN/GaN heterostructures grown on 150-mm silicon substrate (Conference Presentation)

Abstract

AlxInyGa(1-x-y)N/GaN heterostructure is gaining increasing popularity for high power millimetre (mm)-wave high electron mobility transistors (HEMTs) because of its superior electron transport properties. For HEMTs to be able to operate in the mm-wave range, greatly scaled devices with gate length less than 100 nm is necessary. Consequently a sub-10 nm barrier, i.e. a small gate to channel distance, is required to mitigate short channel effects. For this, AlInN/GaN HEMT, which offers high two-dimensional electron gas (2DEG) density, is an alternative to its AlGaN/GaN counterpart. Adding Ga to AlInN might allows the engineering of total polarization, bandgap, and strain of the quaternary alloy independently, providing additional degrees of freedom in device design for performance optimization. Since there have not been many reports on this subject, this study aims at growing high electron mobility, low sheet resistance and high bandgap sub-10 nm AlInGaN/AlN/GaN heterostructures on 150 mm silicon substrates by investigating the role of barrier composition in the transport properties at the heterointerface. Electron mobility of 1,910 cm2/v.s and 2DEG density of 1.33x1013 cm-2, resulting a sheet resistance of 246 ohm/sq. is achieved on an AlInGaN/AlN/GaN HEMT with a 8.7 nm-thick Al0.73In0.08Ga0.19N barrier on a 150 mm Silicon (111) substrate. To our knowledge, this is one of the best electron mobility obtained on AlInGaN HEMTs grown on Si. As indicated by transmission electron microscopy images, it could be attributed to the smooth hetero-interface, which leads to reduced interface roughness scattering.