Carrier transport mechanisms in InSb diffusion p-n junctions

Abstract

Abstract. The linearly-graded p-n junctions were prepared by diffusion of cadmium into n-InSb(100) substrate with the electron concentration n  1.610 15 cm -3 at the temperature T = 77 K. Passivation and protection of mesa structures have been carried out using thin films of CdTe. Forward and reverse current-voltage characteristics were investigated within the temperature range 77…156 K. It has been found that the total dark current consists of generation-recombination and tunneling current components, which are dominant at high (T = 120…156 K) and low (T < 120 K) temperatures, respectively. Experimental results have been explained using the model of a nonhomogeneous p-n junction. It has been shown that in the linearly-graded p-n junction with the rather thick (~1 m) depletion region tunneling current flows through the states related to dislocations in the depletion region. The performed estimation of electrical parameters of diffusion InSb p-n junctions allows to predict behavior of InSb-based photodiodes at operation temperatures T > 77 K.

Carrier transport mechanisms in reverse biased InSb p-n junctions

“…The rectification ratio at 77 K is reached 10 3 at voltages ±250 mV. The carrier transport mechanisms in diffused InSb junctions at direct biases were analyzed in details previously [8].…”

“…Concerning InSb photodiodes, a model of inhomogeneous junction has been successfully used for explanation of direct I−U characteristics [8]. It is natural to assume that the excess reverse current in the investigated junctions is also related to inhomogeneities.…”

“…Experimental results published in literature have contradictory character and suggestions on the nature of the excess current mechanism and are very different. For instance, it was explained by the surface leakage [2] or by tunneling with participation of extended defects (dislocations, precipitates) intersecting the depletion region [8]. In p-n junctions produced by ion implantation with Be or Mg, the interband tunneling current was shown to be dominant at high reverse bias voltages [5,9,10].…”

Electrical properties of InSb p-n junctions prepared by diffusion methods

“…Up to date, 2052×2052 focal matrix is developed on InSb bulk material [2]. The commonly used methods for manufacture InSb p-n junctions are implantation of light ions Be [3][4][5], Mg [3] and Zn [6], as well as diffusion of acceptor impurity Cd [7][8][9][10][11][12]. In diffusion photodiodes, rather high value of the differential resistance -area product R 0 A = 3.4·10 3 Ω·cm 2 was already reported in 1961 [7].…”

“…This model involves uniform distribution of deep traps through the depletion region [8,11]. On the contrary, in a model of non-homogeneous p-n junction, carrier tunnelling with participation of extended defects, such as dislocations, is assumed to be responsible for the excess current [12,14]. In this case, local areas exist in the depletion region, which are characterized by higher electric field.…”