ATOMIC LAYER EPITAXY OF CDTE AND MNTE

Atomic deposition techniques are investigated for binary semiconductor s of the telluride family, namely CdTe and MnTe. An original method fo r directly determining the CdTe atomic layer epitaxy (ALE) growth rate -in monolayers/cycle-is proposed, consisting in monitoring the reflect ion high-energy electron diffraction (RHEED) sublimation intensity osc illations of an ALE grown CdTe layer deposited on a MgTe buffer layer. The ALE CdTe autoregulated growth rate at 0.5 monolayer/cycle (in the substrate temperature domain between 260 and 290 degrees C) is accoun ted for on the basis of an atomic model which relies on the alternatin g c(2 X 2) Cd and (2 X 1) Te surface reconstructions during the ALE cy cle. RHEED studies on MnTe atomic deposition, together with x-ray diff raction and transmission electron microscopy on ALE grown CdTe/MnTe su perlattices reveal that all deposited Mn atoms are incorporated so tha t no autoregulated growth can be achieved. Furthermore, less than one or just one monolayer of Mn must be sent on the surface per ALE cycle to obtain well controlled superlattices with abrupt interfaces. (C) 19 96 American Institute of Physics.