The chemical and electrical characteristics were measured of loo-keV Si+ -implanted GaAs at doses of(6-10) X 10 12 cm-2 after rapid thermal annealing (RTA) for times of 5-40 s at temperatures between 850 and 975°C. Optimal conditions were 5 s at 930°C in either Ar or Ar-H2 atmospheres. Purity of the gas ambient was critical at the higher temperatures. Surface degradation was minimal for face-to-face annealing, as compared to exposed Si0 2 encapsulated surfaces. Essentially identical electrical characteristics were obtained by the preferred RTA conditions as compared to 30-min conventional furnace annealing under optimum conditions at 850°C using the controlled atmosphere technique. The markedly different RTA annealing times with comparable electrical characteristics are attributed to the differences in the host lattice damage recovery resulting from heat transfer and the actual duration to reach the desired anneal temperature.

Rapid thermal annealing (RTA) for the electrical activation of 300-keV Si+ implants in GaAs at doses of (6–8) ×1012 cm−2 is shown to be superior to conventional annealing. Higher gateless field-effect transistor saturation currents and greater uniformities of the saturation current were measured as well as higher peak electron concentrations and mobilities. The advantages of RTA for the removal of ion implantation damage in GaAs are attributed to the heating rate being two orders of magnitude greater than that for furnace annealing. Characteristics are given for single- and four-cell GaAs power metal-semiconductor field-effect transitions fabricated using the above implant and optimized RTA conditions. A 1-μm gate length by 2400-μm gate width device has demonstrated an output power of 1.73 W with 4.9 dB associated gain, 30% power-added efficiency, and 8.1 dB linear gain at 10 GHz.

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The electrical and photoluminescent properties of vanadium incorporated into GaAs epitaxial layers from a VO(OC2H5)3 source during organometallic vapor phase epitaxy were examined. The vanadium concentration in the GaAs was controllably varied from 1016 to 1018 atoms cm−3. Deep level transient spectroscopy showed the presence of an electron trap at Ec−0.15 eV which increased in concentration with vanadium content of the epitaxial layers. A maximum value of 8×1015 cm−3 for this trap was obtained. There were no midgap electron traps associated with vanadium. In intentionally Si-doped epitaxial layers, co-doping with vanadium was observed to have no effect in reducing the carrier density when the Si concentration was ≥4×1016 cm−3. The net carrier concentration profiles resulting from 29Si implantation into GaAs containing 1018 cm−3 of total V had sharper tails than for similar implantation into undoped material, indicating the presence of less than 1016 cm−3 V-related acceptors. Photoluminescent spectra exhibited the characteristic V+3 intracenter emission at 0.65–0.75 eV. No other deep level photoluminescence was detected. For a V concentration of 1016 cm−3 only 2.5×1013 cm−3 was electrically active. Over the entire V concentration investigated this impurity was predominantly (≥99%) inactive.

The redistribution of Mn in Si+ and Se+ implanted Cr-doped semi-insulating GaAs substrates is studied by secondary-ion mass spectrometry as a function of implant dose, energy, and annealing temperature subsequent to annealing capless and with a SiO2 cap in a As4-H2 atmosphere. Mn accumulates within a depth of 0.5 μm from the GaAs surface with a peak at ∼500 Å from the surface for capless anneals. The Mn peak position is constant as the implant energy is varied. The role of the encapsulant in gettering Mn is described. The observed accumulation of Mn near the surface region of GaAs can cause p-type conversion of this region as reported by Klein. A higher solid solubility (≊ 3×1018 atoms/cm3) and a higher diffusion rate of Mn than of Cr in GaAs at 900 °C are indicated by the dose study. A preliminary model for the Mn diffusion mechanism under the above conditions is proposed.