高温下n-GaN/Ti/Al/Ni/Au欧姆接触的可靠性研究

研究了高温工作环境下Ti/Al/Ni/Au(15 nm/220 nm/40 nm/50 nm)四层复合金属层与n-GaN(N_d= 3.7×10~(17)cm~(-3),N_d=3.0×10~(18)cm~(-3))的欧姆接触特性,试验结果标明,当测量温度低于300℃时,存储时间为0～24h,其接触电阻率基本不变,表现出良好的温度可靠性;分别经过300、500℃各24h高温存储后,其欧姆接触发生了较为明显的退化,且不可恢复.接触电阻率均随测量温度的增加而增大,掺杂浓度越高,其接触电阻率随测量温度的升高缓慢增加;重掺杂样品的n-GaN/Ti/Al/Ni/Au欧姆接触具有更高的高温可靠性。

High Temperature Reliability Studied of Ti/Al/Ni/Au Multilayer Ohmic Contact to n-GaN

Study the high temperature characteristics of the ohmic contact of Ti/Al/Ni/Au(15 nm/220 nm/40 nm/50 nm) multiplayer contacts to n-type GaN(N_d=3.7×10~(17)cm~(-3),N_d=3.0×10~(18)cm~(-3)),the experi- ment shows that the contact resistivity keeps unchanged and shows good temperature reliability when the stor- age temperature under 300℃during the storage time of 0～24 hours;but the ohmic contact has shown evi- dent degeneration after the storage at 300℃for 24 hours and at 500℃for 24 hours respectively.Further- more,the contact resisivity shows unrecoverable characteristic.The contact resistivity will increase with the measurement temperature,and the tendency of increasing is related to doping concentration,The higher the doping concentration,the slower of decreasing the contact resistivity with measurement temperature.Ti/Al/ Ni/Au ohmic contact to heavy doping n-GaN better high temperature reliability.