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借助二次离子质谱法分析了注入的钒离子在碳化硅中的分布.即使经过1650℃的高温退火,钒在碳化硅中的再扩散也不显著.退火并没有导致明显的钒向碳化硅表面扩散形成堆积的现象,由于缺少钒的补偿作用,表面薄层的自由载流子浓度保持不变.采用线性传输线模型测量了钒注入n型4H-SiC上的Ni基接触电阻,在1050℃下,在氮、氢混合气体中退火10min,形成的最低比接触电阻为4.4×10-3Ω.cm2.金属化退火后的XRD分析结果表明,镍、碳化硅界面处形成了Ni2Si和石墨相.观测到的石墨相是由于退火导致C原子外扩散并堆积形成,同时在碳化硅表面形成C空位.C空位可以提高有效载流子浓度,降低势垒高度并减小耗尽层宽度,对最终形成欧姆接触起到了关键作用.
The distribution of the injected vanadium ions in the silicon carbide was analyzed by means of secondary ion mass spectrometry and the re-diffusion of vanadium in the silicon carbide was insignificant even after high-temperature annealing at 1650 ° C. The annealing did not result in significant vanadium reaching the silicon carbide surface Diffusion and accumulation, the free carrier concentration of the surface thin film remained unchanged due to the lack of vanadium compensation.The Ni-based contact resistance of vanadium implanted n-type 4H-SiC was measured by a linear transmission line model, and at 1050 ℃ , And annealed in a mixed gas of nitrogen and hydrogen for 10 min to form a minimum specific contact resistance of 4.4 × 10 -3 Ω · cm 2. XRD analysis after metallization annealing showed that Ni 2 Si and graphite phases were formed at the interface between nickel and silicon carbide The graphite phase is due to the diffusion and accumulation of C atoms due to the annealing and the formation of C vacancies on the silicon carbide surface. C vacancy can increase the effective carrier concentration, decrease the barrier height and decrease the width of the depletion layer, Ohmic contact has played a key role.