Improved Thermal Stability and Reduced Contact Resistance of Ohmic Contacts on N-Face n-Type GaN With Laser-Assisted Doping
Improved Thermal Stability and Reduced Contact Resistance of Ohmic Contacts on N-Face n-Type GaN With Laser-Assisted Doping
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DOI：
10.1109/led.2012.2237498
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发表时间：
2013-01
影响因子：
4.9
通讯作者：
Su Jin Kim;T. Jeong;Tae Geun Kim
中科院分区：
文献类型：
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作者：
Su Jin Kim;T. Jeong;Tae Geun Kim
作者报道了激光辅助掺硅降低了N面n-GaN与Ti/Al欧姆接触的接触电阻和热稳定性。在沉积Ti/Al之前，通过在GaN表面进行激光辅助Si扩散，使Ti(30 Nm)/Al(2 0 0 Nm)电极的接触电阻率从7.6 1×10-4降低到8.72×10-5Ω·cm2。在此过程中，Si掺杂原子被认为扩散到GaN中，而Ga-N键被激光辅助掺杂破坏，最终增加了N空位的数量，并在GaN表面产生了Si原子取代Ga的位置。二次离子质谱仪和X射线光电子能谱证实了这一观点。
The authors report reduced contact resistance and improved thermal stability of Ti/Al ohmic contacts to N-face n-GaN via laser-assisted Si doping. The contact resistivity of Ti (30 nm)/Al (200 nm) electrodes was reduced from 7.61 ×10-4 to 8.72 ×10-5 Ω·cm2 by applying laser-assisted Si diffusion to the GaN surface before Ti/Al deposition. Moreover, no degradation in specific contact resistivity was observed for the highly doped samples after annealing at 300 °C. During this process, Si dopant atoms are believed to diffuse into GaN, whereas Ga-N bonds are broken by laser-assisted doping, which eventually increases the number of nitrogen vacancies and generates sites at which Si atoms are substituted for Ga on the GaN surface. This suggestion was verified by secondary ion mass spectrometry and X-ray photoelectron spectroscopy.