Composition-Modulated Structures in InGaAsP and InGaP Liquid Phase Epitaxial Layers Grown on (001) GaAs Substrates

Abstract

InGaAsP and InGaP epitaxial layers lattice-matched to (001)-oriented GaAs substrates successfully grown by liquid phase epitaxy have been investigated by transmission electron microscopy, scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. In both layers, periodic diffraction contrasts (modulated structures), are observed in two equivalent directions of the <100> and the <010>. Compositional variation has also been observed along these structures. These are associated with spinodal decomposition of the crystal during growth.

Compositional modulation and surface stability in InGaP films: Understanding and controlling surface properties

“…Actually, compositional modulation in LPE-grown InGaAsP films 9,10 occurred precisely in the temperature range predicted by the spinodal decomposition diagram calculated by Cremoux et al 23 However, these predicted critical temperatures for the spinodal decomposition are found to be much lower than the typical substrate temperatures for growth techniques working away from thermodynamic equilibrium such as MBE. 13 Additionally, bulk diffusion is expected to be negligible.…”

“…8 Compositional modulation has been first observed for InGaAsP semiconductor alloys grown by liquid phase epitaxy ͑LPE͒. 9,10 However, this bulk phenomenon is not limited to quaternary alloys or to the LPE growth technique. Several works have reported compositional modulation on other semiconductor alloys such as CVD-grown SiGe, 11 MBE-grown InGaAs 12,13 and, more recently, for the InGaP/GaAs system grown by the chemical beam epitaxy ͑CBE͒.…”

Anomalous behavior of phase separation of InGaAsP on GaAs substrates grown by MOVPE

“…Because this phase separation causes degradation of crystal quality, the study on generation mechanism of the immiscibility is necessary for an application to laser diodes. While many researchers have investigated the phase separation of InGaAsP grown by liquid phase epitaxy [2,3], there are only a few studies on metalorganic vapor phase epitaxy (MOVPE) growth [4][5][6]. In the case of MOVPE, specific factors for vapor phase growth such as existence of the surface reconstruction can influence the generation of immiscibility.…”

Coexistence properties of phase separation and CuPt-ordering in InGaAsP grown on GaAs substrates by organometallic vapor phase epitaxy

“…The immiscibility of InGaAsP has been reported in samples grown by liquid phase epitaxy (LPE) [7][8][9][10] and molecular beam epitaxy (MBE) [11]. For example, in the LPE grown InGaAsP, the following concepts have been widely accepted.…”

“…(1) The influence of immiscibility appears prominently in the LPE grown films; the growth rate drops drastically in the composition of the MG [7]. (2) The phase separation of the structure-lateral composition modulation (LCM) is induced in the epitaxial layer; the decomposition appears perpendicular to the growth direction or in the direction along the plane parallel to the growth surface [8][9][10]. These phenomena of the immiscibility have been observed in the MBE-grown InGaAsP layers; however, MBE is the most non-equilibrium growth mode of the available growth methods of InGaAsP [11][12][13].…”