Mg-Based Dual Ion Implantation Technique for High Performance P-channel AlGaAs/InGaAs Heterostructure FETs

We examined a less diffusive and less toxic Mg-based dual ion implantation technique for p⁺-layer formation of p-channel heterostructure field effect transistors (p-HFETs), From ion implantation experiments into GaAs/Al_0.75Ga_0.25As/In_0.2Ga_0.8As heterostructures, P dual implantation is found to be very effective in terms of its low sheet resistance and low Mg redistribution in implanted regions. We then fabricated sub-micron p-HFETs by Mg-based ion implantation and showed the superiority of Mg compared with Be. The device performance was improved by P dual implantation. The peak transconductance and the gate turn-on voltage (defined as the gate-to-source voltage at a gate-to-source current of -1 μA/μm) of 0.5 μm-gate p-HFET fabricated with Mg+P dual implantation are 80 mS/mm and -2.0 V, respectively. This is the best combination among p-HFETs so far reported. We therefore concluded that the Mg+P dual ion implantation technique is promising for forming p⁺-layers in p-HFETs with a short gate length.