Characterization of quaternary Zn/Sn-codoped GaN films obtained with Zn x Sn0.04GaN targets at different Zn contents by the RF reactive magnetron sputtering technology

Quarternary (Zn, Sn, Ga)N thin films with co-existing a large amount of acceptor and donor were purposely fabricated in order to heavily distort the GaN lattice and to extend the degenerated GaN semiconductor to a different aspect. The ZnSnGaN films were made of reactive sputtering with single cermet targets containing Zn, Sn, Ga, and GaN under the nitridation atmosphere. By varying the Zn content at fixed 4% Sn content, different Zn (x) Sn0.04Ga0.96-x N targets at x = 0, 0.03, 0.06, and 0.09 were prepared for Zn/Sn-x-GaN films. With increasing the Zn content, Zn/Sn-x-GaN due to the charge compensation changed from semiconducting n type to p type, and from high electron concentration of 4.1 x 10(17) cm(-3) to high hole concentration of 3.3 x 10(17) cm(-3). The optical band gap changed from 3.12 to 2.89 eV, related to the formation in Zn-Ga acceptor and Sn-Ga donor defects. The hetero- and homo-junction diodes were fabricated. The n-Zn0.03Sn0.04GaN/p-Zn0.09Sn0.04GaN homo-junction diode tested at 25 A degrees C had the turn-on voltage of 0.9 V, leakage current density of 6.0x10(-5) A/cm(2) at - 1 V, breakdown voltage of 4.7 V, current density of 2.4 x 10(-2) A/cm(2) at 5 V, ideality factor of 3.4, and barrier height of 0.65 eV.