一、原理 我们测试高纯锗单晶的纯度是通过将被测试的锗材料制备成探测器,借测量探测器的全耗尽电压和pn结的电容-电压特性来实现的。在探测器的两边有薄的p~+和n~+接触,这两个接触的杂质浓度要比锗材料本身的杂质浓度大得多,因此可以用突变结关系计算探测器的耗尽层厚度。假定在锗材料中的杂质浓度是均匀的,对于一个平面型二极管的耗尽层厚度W=(2εV/qN)~(12)。式中,V为加在二极管上的反向偏压;N为锗单晶材料块的杂质浓度;ε为锗的介电常数:q为电子电荷。由这个公式知道,锗单晶的杂质浓度越低, First, the principle We test the purity of high-purity germanium single crystal germanium material is tested by the detector prepared by measuring the detector fully depleted voltage and pn junction capacitance - voltage characteristics to achieve. There are thin p + and n + contacts on both sides of the detector. The impurity concentration of the two contacts is much greater than that of the germanium itself, so the depletion layer thickness . Assuming that the impurity concentration in the germanium material is uniform, the depletion layer thickness W = (2εV / qN) ~ (12) for a planar diode. Where V is the reverse bias applied to the diode; N is the impurity concentration of the germanium single crystal material block; ε is the permittivity of germanium: q is the electron charge. It is known from this formula that the lower the impurity concentration of germanium single crystal,