GaN紫外探测器的Ti/Al接触的电学特性

Electrical properties of Ti/Al contacts on GaN UV detector

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。

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°C in the ambient gas of N2. 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°C 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. 88×1018cm-3 can form Ohmic contacts without annealing, specific contact resistance of the sample is 4. 03 × 10 -4 Ω cm2.