GAAS DEVICE ISOLATION BY BORON IMPLANTATION

GaAs device isolation caused with Boron ion-implantation damage is effective for realizing GaAs LSIs and high performance microwave devices. In this paper, the electrical properties of the damaged region induced by Boron ion-implantation, as well as the isolation mechanism, are investigated. The optimum Boron implantation dosage for the device isolation is around 10(13)cm-2 with 100 keV acceleration energy. From the temperature dependence of the conductivity, it is found that the damaged layer has activation energies of 0.8 eV and 0.5 eV for LEC (Liquid Encapsulated Czochralski) substrates and MBE (Molecular Beam Epitaxy) layers, respectively. The electric potential distribution between the electrodes indicates that the increase in the ion-implantation damage alleviates the electric field concentration near the anode. According to the numerical analysis, ion-implantation damages, acting as recombination centers, reduce the accumulation of holes in the substrate, and as a result, they increase the threshold voltage for the side-gating effect.