导纳谱研究两类Si基量子阱基态子能级的性质

用导纳谱技术研究了两类Si基量子阱样品基态子能级的性质.基于量子阱中载流子的热激发模型，从导纳谱中得到的激发能值被认为是阱中重空穴基态位置到阱顶的距离.对于SiGe合金和Si形成的组分量子阱，主要研究了退火对重空穴基态子能级的影响.发现样品的退火温度为800℃时，随退火时间延长，激发能增加.对此现象的解释是，由于Si,Ge互扩散，导致界面展宽，量子限制效应降低，重空穴基态位置下降，从而激发能增加.900℃下退火，由于扩散系数增大和应变弛豫加强，激发能值单调下降，量子限制效应引起的变化被掩盖.对于B高浓度超 关键词：

GROUND STATE ENERGY LEVEL OF Si-BASE QUANTUM WELLS DETECTED BY ADMITTANCE SPECTROSCOPY

The admittance spectroscopy technique has been used to study the hole confinement in Si/Si_1-xGe_x/Si and boron highly doped superthin Si quantum wells. Based on the carrier thermal emission medel of the carriers in the well, the value of activation energy derived from the admittance spectra was considered as the distance from the position of the heavy hole ground state in the well to the top of it . For Si/Si_1-xGe_x/Si quantum wells we found the value of activation energy increased with increasing annealing time at 800℃. The phenomena could be explained the annealing-induced interdiffusion of Si and Ge, the interface broadening, the weakening of quantum confinement, the decrease of the position of the heavy hole ground state, and so the increase of the activation energy. At the annealing temperature of 900℃, we only see the decrease of the value of activation energy with increasing annealing time. For boron highly doped superthin Si quantum wells due to quantum confinement effect, we observed the activation energy are different for samples with the same doping density but different well widths.