TEM structural studies on Se+implanted GaAs

Abstract

(100) GaAs slices were implanted with 450 keV Se⁺ ions with the slices at 200°C. Ion doses of 10¹³, 10¹⁴, 5 × 10¹⁴ and 10¹⁵ cm⁻² were used, and the specimens subsequently annealed at 400,500,600,700 and 800°C using A1 as an encapsulant. TEM studies of the damage were made using “plan” and “90° cross-sectional” specimens. Two different types of damage occurred. “Surface” damage extended from the surface to a depth of ∼600 Å, and consisted of fine irregular structure at low annealing temperatures and dislocation lines at high annealing temperatures. “Interior” damage occurred in bands beneath the surface at doses of 10¹⁴ cm⁻² and greater, and consisted of clusters at low annealing temperatures and dislocation loops at high annealing temperatures. In some instances the “interior” damage was present in two discrete bands. The damage often extended to depths of 3 to 4 times the LSS range, and the formation of damage observable by TEM was often retarded when the implanted ion concentration was high.