Fabricating ZnSnN₂ with cosputtering

The deposition of ZnSnN₂ by co-sputtering was studied systematically. Different deposition parameters, including substrate temperatures, N₂ flow rates and different work pressure etc. were tried and the structural, optical and electrical properties were studied. The results show that the deposition parameters to fabricate ZnSnN₂ are relatively wide. The suitable substrate temperature to obtain polycrystalline ZnSnN₂ is around 350 °C when other parameters are kept constant. Relatively larger N₂ flow rate can suppress the formation of metallic phase such as Sn and favour the deposition of ZnSnN₂ with relatively pure phase, with other parameters to be constant. The addition of the substrate bias voltage or a relatively lower power of the Sn target is harmful to the film crystallization of ZnSnN₂. The samples are considered to be wurtzite due to the absence of the orthorhombic (110) and (011) peaks at 20°–22°. The hexagonal lattice constants a and c are about 3.36–3.40 Å and 5.49 Å respectively. The sputtering pressure can affect the structural and electrical properties of ZnSnN₂. ZnSnN₂ prepared at larger work pressure such as 7.0 Pa has a lower electron density (6.72 × 10¹⁹ cm⁻³) and a higher mobility (24.3 cm² V⁻¹ s⁻¹) as compared with those prepared at 1.0 and 3.0 Pa.