Diffusion with Interstitial-Substitutional Equilibrium. Zinc in GaAs

Growth and characterization of buried GaSb p‐n junctions for photovoltaic applications

“…Moreover, Zn mainly occupies substitutional sites in GaAs, since Hall effect and electrochemical capacitance voltage (ECV) profile measurements demonstrate that carrier concentration virtually coincides with the atom concentration obtained by SIMS profiles. It is well known that the diffusion coefficient of substitutional species is negligible if compared with the interstitial ones [10]. In addition, it should not be ruled out a contribution of the misfit dislocations, which most presumably are concentrated along the GaAs/GaSb interface: the line defects, which usually lie parallel to the surface of the sample [11], could act as a barrier for Zn movement, slowing down the diffusion process.…”

Approximate solutions to a nonlinear diffusion equation

“…Problem (2.1) has been studied numerically for m = 1, 2 and 3 by Weisberg and Blanc [27]. Approximation procedures have been suggested by Tuck [25] and by Anderson and Lisak [2], and approximate solutions have been proposed for arsenic by Nakajima et al [19] and for boron by Fair [9].…”

“…Hence the results of this paper based on (1.1) should be regarded as giving the first term in an outer expansion for the concentration. The models of Weisberg and Blanc [27] and Luque et al [18] for zinc diffusion in gallium arsenide may be written in non-dimensional form as For a detailed analysis of the case m = 1, see King [14]. The usually assumed diffusion coefficient for arsenic leads to an algebraically more complicated problem, but a similar analysis holds (see King [15]).…”

Calculation of zinc diffusion profiles in in-based semiconductors by the finite-difference beam propagation method (FD-BPM)

“…This γ is equal to the difference between the valence of the interstitial Zn atoms specified in Eq. (1) and that of the acceptor atoms. In the present calculations γ = 2, since the valence of an interstitial Zn atom is +1 while that of an acceptor is -1 [2].…”

“…An important requirement for the design of devices whose fabrication requires the use of this diffusion technology is prior knowledge of the diffusion density and diffusion depth, usually from computations. The method used to calculate the diffusion density profile is to start with the method of solution transformation [1][2][3], in which the diffusion equation is first converted from a partial differential equation to an ordinary differential equation via Boltzmann's transformation. The latter is then solved by some differencing method.…”