【摘要】 半导体中的深能级杂质缺陷在禁带中往往有好几个能级,如果其中有接近禁带中央的能级,它在载流子复合等问题中起重要作用.本文指出利用接近禁带中央的能级在深能级瞬态谱(DLTS)中的峰高与其它能级的峰高的比值或利用相应的瞬态电容的初始值的比值,可以求出接近禁带中央的那个能级的电子热发射率与空穴热发射率的比值C_n(T)/e_p(T),结合DLTS的率窗或瞬态电容的时间常数,可以同时确定该能级的e_n(T)及c_p(T),并可进而求出该能级在禁带中的位置、禁带宽度在绝对零度的外插值等参数.以掺金的硅为例应用上述方法,在较高的温度范围用DLTS,在较低的温度范围用瞬态电容,求得了金的受主能级的c_n(T)/c_p(T).c_n(T)、c_p(T)及其它参数,与文献所载的用其它方法求出的相近.文中还讨论了这种方法的误差以及这种方法在识别杂质缺陷方面的可能作用.更多还原

【Abstract】 Deep-level impurity or defect centres in semiconductors are very often multiple-levelled.It is shown that if one level of such a multiple level centre is near mid-gap,one can obtain the ratio of its electron and hole emission rates e_n(T)/e_p(T) (thermal)from the ratio of its DLTS peak to that of another level of the centre (or from theratio of their initial transient capacitances).With additional use of the value of theDLTS rate window (or time constant of the transient capacitance), the values of e_n(T)and e_p(T) of the mid-gap level can be separately determined.Therefore one canfurther determine the level position in the gap and the extrapolated value of theforbidden gap width at OK.DLTS (high temperature) and transient capacitance(low temperature) measurements have been made on Au-doped Si and the value fore_n(T)/e_p(T), e_n(T), e_p(T) of the gold acceptor level are determined.The results areclose to those obtained by other methods as reported in the literature.The accuracyof the method is discussed and the possibility of using this method for identificationof impurity and defect centres is indicated.更多还原