Zinc diffusion in InGaAsP

Abstract

Ampoule diffusion of Zn in undoped liquid phase epitaxial InGaAsP layers between 425 and 525 °C shows the Zn solubility, as measured with secondary ion mass spectrometry, to be much larger than in InP and to be slightly less than in GaAs. The acceptor concentration, as determined by capacitance-voltage measurements, is 60%–90% of the Zn concentration. Incorporation and diffusion of Zn can be described with the interstitial-substitutional model. The difference between the acceptor and Zn concentrations can be explained by compensating Zn interstitial donors or by neutral Zn-vacancy complexes. The diffusion depth is slightly smaller than in InP and much larger than in GaAs. In n-type InGaAsP, profiles are found with a cut-off similar to the behavior in InP. The solubility is higher than in undoped InGaAsP.

Stability of Zn doping profile in modulation-doped multiple quantum well structure

“…9. 18,[26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] The value obtained in this work is ten thousand times lower than the reported diffusion coefficient of 6.5ϫ10 Ϫ14 cm 2 /s. 42…”

“…34 The interstitial Zn produced in the p-InP layer is also built in as the substitutional Zn and then interstitial group III atoms III (i) are produced as described in the kick-out mechanism 50…”

“…21 The often observed high diffusivity of Zn atoms would seem to restrict the possibility of getting abrupt doping profiles. [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] However, doping superlattices ͑so-called nipi structure͒ with Zn as p-type dopant have been successfully fabricated. [22][23][24][25] Furthermore, a small Zn diffusion coefficient of 6.5ϫ10 Ϫ14 cm 2 /s has been reported in the case of unin-tentional diffusion.…”

InP-based photonic circuits: Comparison of monolithic integration techniques

“…This is achieved with Zn-doping. However, Zn is known as a fast diffuser in InP [64], therefore some precaution should be made for the first InP-cladding layer, to avoid converting it to p-type. If the layer is grown non-intentionally n-doped at 5 Â 10 15 cm À3 then the whole (200 nm) layer will be converted to p-type up to the Q1.25 interface during the growth step of Fig.…”

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

“…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.…”