Improving electrical transport properties of AlGaN/GaN heterostructure using AlSiN passivation

AlGaN/GaN heterostructures have been widely used in modern high power and high frequency device applications due to their excellent material characteristics. However, the existence of surface damages, defects and dislocations may degrade the device features. Here, we report the effect of AlSiN surface passivation on electrical transport properties in AlGaN/GaN heterostructure. Compared with the unpassivated, AlN and AlBN passivated AlGaN/GaN, better transport properties have been observed in the AlSiN passivated samples. Both the density and mobility increase in the AlSiN passivated AlGaN/GaN, which may be attributed to the influence of the AlGaN/GaN interface barrier height and suppression of trapping effects. The results show that AlSiN dielectric films is a very promising candidate as surface passivation for AlGaN/GaN HEMTs.