A capless rapid thermal annealing method has been used to activate Be atoms implanted into n‐In0.52Al0.48As. The dependence of electrical activation upon various annealing conditions has been investigated. Annealing at 800–850 °C for 2–3 s yields high electrical activation. Activation efficiencies of 76% and 49% are achieved on InAlAs layers with implant doses of 2×1013 and 2×1014 cm-2, respectively. The lowest sheet resistivity obtained was 2.2 kΩ/⧠ at an implant dose of 1.5×1014 cm-2. Electrical characteristics of Be‐implanted p+‐n InAlAs diodes are also presented. The forward diode currents were dominated by recombination current components at room temperature. The reverse leakage currents increase with increasing implant doses. Diodes annealed at 800 °C for 2–3 s have the lowest reverse leakage currents.