GaN紫外探测器的Ti/Al接触的电学特性

在非故意掺杂的和掺Si的GaN薄膜上蒸镀Ti(24nm)/Al(nm)薄膜,氮气环境下400～800℃范围内进行退火。实验结果表明,在非故意掺杂的样品上,随退火温度的升高,肖特基势垒高度下降,理想因子升高,表面状况逐渐变差,600℃退火形成较低接触电阻的欧姆接触,比接触电阻率为3.03×10-4Ωcm2,而载流子浓度为5.88×1018cm-3的掺Si的样品未退火就形成欧姆接触,比接触电阻可达到4.03×10-4Ωcm2。

Electrical properties of Ti/Al contacts on GaN UV detector

Ti(24 nm)/Al(90 nm) film was deposited on unintentional doped GaN and Si-doped GaN to form metal/semiconductor contacts ,which were annealed at 400～800℃ in the ambient gas of N2.The result shows that Schottky barrier height decreases , ideal factor increases and surface condition of contacts degenerates when annealing temperature increases for unintentional doped GaN. The sample at 600℃ annealing forms Ohmic contacts with low specific contact resistance of 3.03×10~(-4) Ω cm~2. However, the sample for Si-doped GaN with carrier concentration of 5.88×10~(18)cm~(-3) can form Ohmic contacts without annealing, specific contact resistance of the sample is 4.03×10~(-4)Ω cm~2.