Experiments on B+ implantation for isolation processes in GaAs MMICs manufactured on MESFET wafers

In this paper are presented experimental results concerning the dependence of the isolation resistance versus the implant doses and the implant energy, for boron implanted ions into the GaAs MESFET epitaxial wafers. It is shown that the dose level is not critical; very good isolation for MMICs may be obtained for ions dose of 6 10¹¹-1 10¹² ions/cm². Also, it is experimentally shown that the isolation characteristics are stable up to at least 200°C, but at 450°C the isolation resistance is small due to the annealing process which decreases the lattice disorder. So, the ohmic contacts based on the AuGe-Ni system (450°C allowing temperature) must be realised before the boron isolation