On the nonlinearity of Ip/Ipo-Vb in the boundary biased-probe method

Using the boundary biased-probe method, the nonlinearity of I_p/I_po-V_b in experiment is contradictory to the linearity of one in Tassicker´s formula applied to this method. In this paper, the authors analysed the model of this method theoretically, and obtained a nonlinear relation of I_p/I_po-V_b in the method. The analysis showed that as a result of this nonlinearity the space charge near the biased-probe affects the probe current I_P and pointed out that this effect had been omitted in Tassicker´s formula. The theoretical analysis and experimental results with this method showed that Tassicker´s formula ought to be improved, especially under rich space-charge condition. The authors proposed a way to improve this formula