Low-Temperature and Ammonia-Free Epitaxy of the GaN/AlGaN/GaN Heterostructure

Wide band-gap semiconductors are very attractive because of their broad applications as electronics and optoelectronics materials, GaN-based materials being by far the most promising. For the production of such nitride-based optical and power devices, metal–organic chemical vapor deposition (MOCVD) is routinely used. However, this has disadvantages, such as the large consumption of ammonia gas and the need for a high growth temperature. To go beyond such a limit, in this study we successfully developed a remote plasma MOCVD (RP-MOCVD) approach for the epitaxial growth of high-quality GaN/AlGaN heterostructures on 4H-SiC substrates. Our RP-MOCVD has the advantages of a lower growth temperature (750 °C) compared to the conventional MOCVD route and the use of a remote N2/H2 plasma instead of ammonia for nitrides growth, generating in situ the NHx (x = 0–3) species needed for the growth. As assessed by structural, morphological, optical, and electrical characterization, the proposed strategy provides an overall cost-effective and green approach for high-quality GaN/AlGaN heteroepitaxy, suitable for high electron mobility transistors (HEMT) technology.