Growth and characterization of GaN/AlGaN high-electron mobility transistors grown on p-type Si substrates

In order to grow high-quality GaN, we often choose sapphire as our substrates. However, silicon can be regarded as a new substrate due to its low cost and large wafer size. It is known that the difficulty of growing GaN on silicon is their large lattice mismatch (∼17%) and thermal mismatch (∼54%) between GaN and silicon. The usual process to reduce such mismatches is to grow an AlN layer as an intermediate layer. In this paper, we inserted a thin SiN layer between GaN and AlN to improve the quality of GaN, and the result showed that such thin SiN layer could greatly enhance the mobility of 2DEG formed at the interface of AlGaN and GaN. This suggests that it is possible to grow high-quality GaN on silicon as well as on sapphire with more studies of growth techniques.