Structural Decomposition at Sn/GaAs(001) Interface

Abstract

ABSTRACTMorphological studies of the system Sn/GaAs(001) are required to interpret electronic anomalies of devices which include doped III-V MBE grown thin films. Previous studies focused on the dynamics of Sn on As terminated surfaces. The current study complements those studies on a Ga terminated surface, i.e., conditions which may occur locally for short periods during MBE growth.Sn is deposited on in-situ cleaned Ga rich GaAs(001) surfaces and the evolution of morphological structures is presented as a function of annealing temperature and Sn supersaturation. Three distinct regimes were observed, (i) a low temperature range (T ≤ 500°C) where Sn shows a propensity toward three-dimensional clustering, (ii) an intermediate temperature range (500°C ≤ T ≤ 625°C) where a transition in the morphology occurs due to strong interactions with the substrate resulting in the formation of characteristic etch-patterns and (iii) a high temperature regime (T ≥ 650°C) where the thermal decomposition of GaAs dominates while the deposited Sn desorbs fast.