通过激光辐照固态Al膜,制备了一种p型重掺杂4H-SiC,分析了Al膜厚度、激光脉冲个数对掺杂结果的影响,验证了不同工艺参数对p型掺杂层表面电学性能的调控作用。结果表明,当Al膜厚度为120 nm,脉冲个数为50时,掺杂试样的最大载流子浓度为6.613×10 ¹⁷ cm ^-3,最小体电阻率为17.36 Ω·cm,掺杂浓度(粒子数浓度)可达6.6×10 ¹⁹ cm ^-3。4H-SiC的Al掺杂改性机理为:在紫外激光作用下,Si—C键断裂,Al原子替代Si原子形成p型掺杂层。

The preparation of p-type heavily-doped 4H-SiC is conducted by using the laser irradiation of solid Al film. The effects of the Al film thickness and the laser pulse number on the doping results are analyzed and the control of different process parameters to the electrical properties of p-type doped layers is verified. The results show that the maximum carrier concentration is 6.613×10 17 cm -3, the minimum volume resistivity is 17.36 Ω·cm, and the doping concentration (particle number concentration) is 6.6×10 19 cm -3, when the Al film thickness is 120 nm and the pulse number is 50. The Al doping modification mechanism of 4H-SiC can be described as the formation of p-type doped layer as a result of the Si—C bond breaking and the replace of Si by Al under the ultraviolet laser irradiation.