摘要
高压液封直拉法生长的未掺杂半绝缘GaAs和水平法生长的掺Cr的半绝缘GaAs二种样晶在有As气氛和没有As气氛保护下分别在真空封管中在740℃退火4小时后,电学测量发现有As气氛保护的GaAs表面未出现热反型,而没有As气氛保护的GaAs表面出现热反型层。光致发光谱测量发现在热反型的样品中并没有出现与Mn_(Ga)相连系的1.41eV发射峰,而是与C_(As)相连系的1.490eV发射峰强度在退火后大大增强。一系列实验表明在真空退火后SI-GaAs表面低阻反型层的产生可能是由于在热退火过程中表面产生的大量V_(As)向内扩散,使表面层中的Ci填充V_(As)形成C_(As),从而使表面层的C_(As)受主浓度增加,导致形成低阻反型层。
Cr-doped and undoped Semi-insulating GaAs, grown by horizontal Bridgeman and Liquid Encapsulaed Czochvalski methed respectively, were annealed in vacuum with/ without arsenic atmosphere at 740℃ for 4 hours. After annealing, electric measurements found that the surface of GaAs heated in As atmosphere did not appear thermal conversion, while the surface of GaAs heated without As atmosphere appeared thermal conversion. PL measurements found that there were not 1.41 eV emission peak related to MnG2 in the samples of thermal conversion and the intensity of 1.490 eV emission peak related to CA3, increased greatly with annealing. A series of experiment showed that due to the diffusion of arsenic vacancy produced during vacuum annealing from surface to internal, Some carbon atoms were able to transform from interstitial (Ci) into acceptors CA3. So the concentration of acceptors CA3 increase near surface, resulting in the thermal conversion layer.
出处
《北京大学学报（自然科学版）》
CAS
CSCD
北大核心
1989年第1期102-109,共8页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
国家自然科学基金资助
关键词
砷化镓
材料
热反型
Thermal conversion
Semiinsulating CaAs
