Electrical and structural characteristics of tin-doped GaN thin films and its hetero-junction diode made all by RF reactive sputtering

Tin (Sn) doping in gallium nitride (GaN) has been mainly reported from the theoretical view only. Based upon the availability of Sn precursor and commercialization, Sn-GaN film has not been deposited magnetron sputtering until this work. By using the cheap and safe reactive sputtering technique, here we present Sn-GaN thin films with single cermet targets at the Sn/(Sn+Ga) molar ratios of x=0, 0.03, 0.07, and 0.1 to form Sn-x-GaN films under the atmosphere of the mixture of Ar and N2. The Sn-GaN films had the wurtzite structure. Sn can be added to GaN to form SnGaN alloy with a maximal amount of ~10%. The structural, electrical, and optical properties had changed with the Sn content until the oversaturation of Sn in Sn-0.1-GaN. The Sn doping led to the lattice expansion, worsened crystallinity, n-type GaN, increased electrical concentration, decreased the electrical mobility etc. Moreover, n-Sn-x-GaN/p-Si diodes were successfully made and their performance was evaluated in terms of the barrier height, ideality factor, and series resistance. This work has opened the door for studying the different kinds of dopants on the important III nitrides.