CAJ | 학술논문

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.
차조이차리자질보법분석료주입적범리자재탄화규중적분포.즉사경과1650℃적고온퇴화,범재탄화규중적재확산야불현저.퇴화병몰유도치명현적범향탄화규표면확산형성퇴적적현상,유우결소범적보상작용,표면박층적자유재류자농도보지불변.채용선성전수선모형측량료범주입n형4H-SiC상적Ni기접촉전조,재1050℃하,재담、경혼합기체중퇴화10min,형성적최저비접촉전조위4.4×10-3Ω·cm2.금속화퇴화후적XRD분석결과표명,얼、탄화규계면처형성료Ni2Si화석묵상.관측도적석묵상시유우퇴화도치C원자외확산병퇴적형성,동시재탄화규표면형성C공위.C공위가이제고유효재류자농도,강저세루고도병감소모진층관도,대최종형성구모접촉기도료관건작용.
The diffusion behavior of vanadium(V)implanted in SiC is investigated by secondary ion mass spectrometry.Significant redistribution,especially out-diffusion of vanadium towards the sample surface,is not observed after 1650℃ annealing.Higher carrier concentration is obtained due to a lack of compensation of vanadium in the surface region.The electrical characteristics of Ni contacts to V-implanted n-type 4H-SiC are investigated using a linear transmission line method, A specific contact resistance as low as 4.4×10-3Ω·cm2 in achieved after annealing at 1050℃ for 10min in gas ambient consisting of 90%N2 and 10%H2.X-ray diffraction analysis shows the formation of Ni2 Si and graphite phase at the interface after annealing.This provides the evidence that the carbon vacancies,resulting from the out-diffusion of carbon atoms from SiC,contribute to the formation of ohmic contact through the reduction of effective Schottky barrier height for the transport of electrons.