Journal of Crystal Growth 110 (1991) 955—959 955 North-Holland Letter to the Editors On the peculiarities of the short-time (tg < 10 ms) solid solution LPE growth onto the moving substrate D.Z. Garbuzov, E.V. Zhuravkevich, A.I. Zhmakin, Yu.N. Makarov and A.V. Ovchinnikov A.F. loffe Physical Technical Institute, Academy of Sciences of the USSR, Leningrad 194021, USSR Received 26 February 1990; manuscript received 16 October 1990 The peculiarities of InGaAsP ultra-thin layer LPE deposition onto a moving substrate are discussed. The abnormal dependency of the layer thickness on the growth melt supersaturation was found at sliding velocity higher than 0.1 rn/s. The growth cell shape was shown to be the main factor affecting the thickness of the deposited layer at growth times shorter than 10 ms. The melt motion influence on the LPE deposition process at high sliding velocities is discussed. The possibility of ultra-thin InGaAsP layer (d This paper deals with the peculiarities of ~ 2 x 106 cm) LPE deposition was demonstrated quaternary InGaAsP solid solution growth at high by Holonyak and co-workers [1—3] using a spe- speed of substrate movement providing growth cially designed revolving boat system. Later, the times from 30 to 0.5 ms. The quaternary InGaAsP InGaAsP/InP and InGaAsP/GaAs low threshold, layers, sandwiched between two wide band-gap Separate confinement quantum-well lasers with ternary InGaP layers, were investigated (fig. 1). active layer thickness, down to 40 A, were grown We utilized (111)A oriented GaAs substrates and by another LPE version utilizing translational sub- a specially designed computer-controlled LPE in- strate movement [4]. These results stimulated the stallation. A computer-guided linear electromag- investigation of thin layer LPE deposition onto a netic motor provided the quick (up to 5 m/s) moving substrate [5,6]. uniform sliding movement of the substrate under Garbuzov et al. [6] noticed that the layer thick- the growth solution. ness distribution was uniform within 25 mm sub- The quaternary layers were grown by a step- strate length at growth time (tg) shorter than 0.2 s. cooling (T = 750°C) method utilizing a graphite This was explained by the presence of convection boat with growth cells of various shapes. Cross- flows in indium-based growth solutions, providing sectional views of the growth cells are shown in the time-independent reagents’ gradient in the fig. 2. Besides the conventional growth cells (fig. vicinity of the substrate. Rezek et al. [7] observed another peculiarity of - LPE deposition onto the moving substrate. The E~,eY layer thickness was found to be independent of It~t~O.P _______ the growth time at tg — 10 ms. Such a phenome- non was explained in ref. [2] by means of surface 15 attachment kinetic processes of atoms from the 1~i1nA~P thin film of liquid contacting the substrate. It was suggested that the real time of 200 A thickness layer growth is much less than the smallest achieved time = 0.5 ms. Fig. 1. Band diagram for LPE-grown heterostructures. 0022-0248/91/$03.50 © 1991 — Elsevier Science Publishers B.V. (North-Holland)