沉积参数及退火条件对AlN薄膜电学性能的影响

Effect of deposition parameters and RTA conditions on electrical properties of AlN thin films

利用射频反应磁控溅射在Si(100)基底上沉积AlN介质薄膜,并在不同温度下对薄膜进行快速退火。通过抗电强度测试仪、电容电压测试C-V、X射线衍射仪、电子能谱仪、原子力显微镜和椭圆偏振仪等研究薄膜的击穿电压、介电常数、晶体结构、化学成分、表面形貌及薄膜的折射率。结果表明:溅射功率和溅射气压对薄膜的击穿电压有很大的影响,溅射功率为250 W,气压为0.3 Pa时薄膜的抗电性能较好;薄膜的成分随溅射气压发生变化,N与Al摩尔比最高达到0.845;随退火温度的增加,薄膜晶体结构发生非晶—闪锌矿—纤锌矿的转变;薄膜的折射率随退火温度的升高而增加。

AIN dielectric thin films were deposited on N type Si （100） substrate by reactive radio frequency magnetron sputtering under different sputtering-power and total pressure. And rapid thermal annealing （RTA） was preformed on these films respectively for 5 min under different temperatures. The breakdown voltage, permittivity, crystal structure, composition, surface and refractive index of the thin films were studied by I-V, C-V, XRD, EDS, AFM and elliptical polarization instrument. The results show that the breakdown voltage of the thin films strongly depends on the sputtering-power and total pressure, the greatest breakdown voltage is found at 250 W and 0.3 Pa. EDS analysis shows that the mole ratio of N to Al of AIN thin films changes with total pressure, and reaches its peak value of 0.845 at 0.3 Pa. The crystal structure of the as-deposited thin-films is amorphous, then it transforms from blende structure to wurtzite structure as the rapid thermal annealing（RTA） temperature changes from 600 to 1 000 ℃. The refractive index also increases with the RTA temperature.