G. Bougnot

Growth of Ga1−xAlxSb and Ga1−xInxSb by organometallic chemical vapor deposition

Abstract Organometallic chemical vapor deposition of Ga 1− x Al x Sb ( x ⩽0.5) and for the first time Ga 1− x In x Sb ( x ⩽0.5) using trimethylgallium, trimethylantimony, trimethylaluminium and trimethylindium has been obtained on GaSb and GaAs substrates. The experimental set and the growth conditions are detailed. On GaSb substrates, surface morphologies of Ga 1− x Al x Sb epitaxial layer are satisfactory but Ga 1− x Al x Sb layers exhibit a degradation of their X-ray diffraction spectra with increasing lattice mismatc Solid compositions as functions of vapor phase compositions and growth temperatures are discussed on the basis of simple kinetic considerations.

Croissance par épitaxie en phase liquide et diagramme de phase du système Ga1−xAlxSb

Abstract The liquids and solidus lines in the Ga-rich region of the Ga-Al-Sb system have been established. The weight loss technique was used to determine the liquidus data at 500, 518 and 536°C. Solidus data were measured by means of electron beam microprobe analysis on epitaxial layers. A phase diagram which is in excellent agreement with these experimental data has been obtained. The calculations are based on a quasi-regular solution model for the three binary liquids and on an ideal solution for the ternary solid.

He´te´ro-e´pitaxie de ZnSe sur GaAs par transport en tube ouvert

Abstract The epitaxial growth of ZnSe on (111) and (100) oriented substrates of GaAs, using an open (HCl-H 2 ) transport process is described. Various factors are discussed which are found to affect the epitaxial growth: the degree of supersaturation and the condensation on the quartz walls are important factors in controlling the growth of II–VI compounds. Resistivities of 10 -2 -1 Ω cm for a p-type conductivity were obtained for layers grown by H 2 transport, but layers obtained from HCl transport have a high resistivity. Photoluminescence studies at 4.2 °K indicated that the luminescence centers are related to Zn and/or Se vacancies.

Improvement of the crystalline, optical and electrical quality of MOVPE GaInSb layers

Ga1−xInxSb layers (x<0.37) are grown on GaSb and GaAs substrates with various initial growth processes including GaSb, SLS, graded or step buffers; the effect of varying the III/V ratio is also observed. The improvement of the morphology, crystalline, electrical and optical quality related to these different ways are examined using optical imaging, X-ray diffraction, 2 K photoluminescence and Hall effect measurements.

Effets D'interaction entre substrat, dépôt et gaz vecteur lors de l'épitaxie de ZnSe sur GaAs

Abstract Hetero-epitaxial growth of ZnSe on semi-insulating GaAs substrates has been studied, using the (H 2 ZnSe) and (H 2 HCl ZnSe) vapour growth technique. Single crystals layers of 1–25 μm in thickness were obtained at growth rates of 0.5−3 μmh −1 . Scanning electron microscope has been found to be a powerful tool in examining the junction structure ZnSe/GaAs. Gallium and arsenic profiles were recorded at the hetero-epitaxial interface and in the ZnSe layer. The role of a chemical reaction including substrate reactivity and formation of the zinc selenide is proven by our results.

Growth kinetics of LPE Ga0.83Al0.17Sb layers grown from supercooled solutions

Abstract GaSb and Ga 0.83 Al 0.17 Sb alloys were grown by liquid phase epitaxy from supercooled solutions. The composition profiles were determined and the thicknesses of the layers were measured as a function of the growth time and the cooling rate. The data are quantitatively consistent with a simple diffusion limited growth model, available for binary and ternary compounds. The diffusivity of antimony was found to be D Sb =7.1×10 -5 cm 2 s -1 for GaSb (at 560°C) and D Sb =6.7×10 -5 cm 2 s -1 for Ga 0.83 Al 0.17 Sb (at 550°C).

Liquid phase epitaxy of heavily Te doped Ga1−xAlxSb on GaSB

Abstract Heavily tellurium doped Ga 1− x Al x Sb alloys were grown by liquid phase epitaxy on p-GaSB undoped substrates. For high Te content liquid solutions ( X L Te ⪕ 0.5 at%), quaternary Ga 1− x Al x Sb 1− y Te y solid solutions were deposited, with Y concentrations up to 0.23 near the substrate-alloy interface. The effective segregation coefficient of tellurium was found to be k eff = 23 at 500°C and k eff = 12 at 550°C. An n-type conductivity was observed with an upper electron density n = 3 × 10 18 cm -3 . Measurements of the electron beam induced current by SEM have shown that the n-p junctions were situated at the chemical interface, with hole diffusion lengths of about 1 цm, and electron diffusion lengths of about 2 цm.

Croissance et caractérisation de couches ZnSe, ZnS et ZnSxSe1-x épitaxiées sur flourine

Abstract Epitaxial films of ZnSe, ZnS and ZnS x Se 1- x , 3 to 12 αm thick and of 1 cm 2 area, have been grown by the vapour phase chemical reaction technique, on the cleavage faces of CaF 2 . Microscopic and X-ray investigations have shown that these compounds crystallized in the cubic phase, in the 600–650°C range of temperature. Some indications are given about the photoluminescence spectra of the ZnSe/CaF 2 layers.

Liquid phase epitaxial Ga0.96Al0.04Sb p/n junctions

Abstract The liquid phase epitaxial growth of successive n- and p - Ga 0.96 Al 0.04 Sb layers is described. The equivalent doping level of the resulting junction is shown to be much lower than the limiting values of the n- and p-concentrations of individual homogeneous layers. A model is proposed to explain this interface concentration reduction. The photoelectrical properties of the devices realized from these p/n junctions are analysed; we show that the reverse current maybe as low as 2.5 uA for a 360 um diameter device at 300 K; the multiplication of the photocurrent I ph has been evaluated to be a value reaching 3 at a polarization range of – 20 V.