Ion implantation and rapid thermal annealing of Mg, Cd, and Si in AlxGa1−xAs grown by molecular-beam epitaxy

Abstract

Ion implantation and rapid thermal annealing of Mg, Cd, and Si in AlxGa1−xAs are reported. The dependence of activation on various Al compositions (x=0.15–0.35) and annealing temperatures was investigated. Activations of over 60% were achieved for both Mg and Cd. However, for the same annealing cycle, the activation efficiency of the Mg implants was found to be generally higher than that of Cd implants. No particular dependence of the activation efficiency on Al composition was observed for either ion. For Si29 implants, poor activation was observed in samples with x above 0.2, while for x=0.2 a maximum activation of 80% was achieved with a 1000 °C, 5 s annealing cycle.

n-type ion implantation doping of AlxGa1−xAs (0⩽x⩽0.7)

“…n s is seen to be relatively constant for a given dose out to 20% AlAs, dramatically decreases at 35% AlAs, and then increases at the higher Al fractions ͑50% and 70% AlAs͒. It should be noted the samples studied by Adachi 4 and Lam 5 were reported as being 30%-35% AlAs, near the minimum for Fig. 3, while the sample in the study by Pearton 6 was 54% which is on the increasing portion of the curve in Fig.…”

“…4 Lam conducted a study including a larger range of Al fractions ͑15%, 20%, 25%, 30%, and 35% AlAs͒ of MBE AlGaAs for a 70 keV Si implant at a dose of 1.5ϫ10 13 cm Ϫ2 and showed the effective activation efficiency ͓ eff ϭ100ϫ ͑sheet electron concentration/implanted dose͔͒ drops from close to 60% for 20% AlAs to 5% or less for the higher Al fractions. 5 A clear description of why eff decreased was not presented by Lam. 5 Additional work was reported for three Al percentages ͑0%, 9%, and 54% AlAs͒ in metalorganic chemical vapor deposition ͑MOCVD͒ grown AlGaAs by Pearton for 100 keV Si at a dose of 1ϫ10 13 or 1ϫ10 14 cm Ϫ2 .…”