半绝缘GaAs热稳定性的研究

Investigation of Thermal Stability of Undoped Semi-Insulating GaAs

用霍尔效应、红外吸收和二次离子质谱方法对不同碳(C)含量的未掺杂半绝缘(SI)GaAs晶体的热稳定性进行了研究,发现EL2浓度([EL2])相近、碳浓度([C])不同的样品中,高碳含量的样品更易出现热转型.长时间热处理后,样品反型层中的载流子浓度超过了[C].这些结果表明,热处理过程中样品表面层不仅发生了施主中心EL2的外扩散,而且有新的受主中心产生.

Thermal stability of undoped LEC semi-insulating GaAs crystal with various carbon contents are investigated using Hall-effect measurement, secondary ion ass spectrometry and infrared spectroscopy absorption measurement techniques. The EL2 concentrations of all samples are about the same. It is found that p-type thermal conversion is formed more easily in samples with the high carbon content than with the low carbon content. The carrier concentration in p-type conversion surface of a long-time annealed sample is higher than carbon concentration. These results suggest that EL2 centres are reduced and native acceptors are created in a surface region by annealing.