Enhanced AlScN/GaN Heterostructures Grown with a Novel Precursor by Metal–Organic Chemical Vapor Deposition

Abstract

Growth of AlScN high‐electron‐mobility transistor (HEMT) structures by metal–organic chemical vapor deposition (MOCVD) is challenging due to the low vapor pressure of the conventionally used precursor tris‐cyclopentadienyl‐scandium (Cp3Sc). It is shown that the electrical and structural characteristics of the AlScN/GaN heterostructure improve significantly by using bis‐methylcyclopentadienyl‐scandiumchloride ((MCp)2ScCl), which has a higher vapor pressure and allows for an increased molar flow and thus higher growth rate (GR). AlScN/GaN HEMT heterostructures with superior electrical characteristics deposited at different barrier growth temperatures are presented. The sheet resistance of 172 Ω sq−1 obtained at 900 °C barrier growth temperature is among the lowest reported so far for AlScN/GaN HEMT structures. The sheet charge carrier density is and the electron mobility μ is 1124 cm2 Vs−1.