High electron mobility AlGaN/GaN have been successfully grown on low cost and high challenges AlN/Si substrates. By inserting a thin SiN layer between GaN and AlN to improve the quality of GaN, the result showed that the thin SiN layer could greatly increase the mobility of the twodimensional electron gas formed at the interface of AlGaN and GaN layers. This suggests that it is possible to grow high-quality GaN on silicon as well as on sapphire for many applications