碳化硅中氦离子高温注入引入的缺陷及其退火行为的光谱研究

对氦(He)离子高温(600K)注入6H-SiC中的辐照缺陷,在阶梯温度退火后演化行为的拉曼光谱和室温光致发光谱的特征进行了分析.这两种方法的实验结果表明,离子注入所产生晶格损伤的程度与注入剂量有关;高温退火导致损伤的恢复,不同注入剂量造成的晶格损伤需要不同的退火温度才可恢复.在阶梯温度退火下呈现出了点缺陷的复合、氦-空位团的产生、氦泡的形核、长大等特性.研究表明:高温(600K)注入在一定剂量范围内是避免注入层非晶化的一个重要方法,为后续利用氦离子注入空腔掩埋层吸杂或者制备低成本、低缺陷密度的绝缘层上碳化硅(SiCOI)材料提供了可能.

6H-SiC single crystal specimens were implanted at 600 K with 100 KeV He ions to three successively increasing fluences and subsequently annealed at different temperatures ranging from 600 degrees C to 1200 degrees C in vacuum. After the annealing, the samples were investigated by using Raman scattering spectroscopy and photoluminescence spectrometry, respectively. Both of the two methods showed that the damage induced by helium-ion-implantation in the lattice is closely related to the dose. The thermal annealing brings about recovery of the damage,and different levels of damage require different annealing temperature to recover efficiently. It is indicated that different annealing stages involve different mechanisms, corresponding to recombination of point defects, formation of He-vacancy complexes, and nucleation and coarsening of bubbles, respectively. The experimental results indicate that high temperature implantation is an effective way to avoid amorphization of the implanted layer due to damage accumulation. Helium implantation can be used to introduce buried nanoscale cavities as the nucleation site for the buried oxide in a well defined region proposed for an altemative and more economical method of manufacturing SiC-on-Insulator (SiCOI).