| 摘要 |
PURPOSE:To prevent the generation of an abnormal phenomenon of a channel layer to low resistance by prescribing the concentration of Cr in a GaAs substrate to some value or lower in response to a distance between a gate and a source of an E-FET in the integrated circuit. CONSTITUTION:When an activated layer is formed to the semi-insulating GaAs substrate through an ion implantation method and the E-MESFET is manufactured, the concentraton NCr of Cr in the substrate is prescribed to some value or lower in response to the disponse to the distance lsg between the gate and the source in the integrated circuit. NCr<=0.2wtppm is allowed when lsg 3mum is formed, NCr<=0.05wtppm when lsg 2mum is formed and NCr<=0.02wtppb when lsg 0.5-1mum is formed. An abnormal phenomenon generating region in which the channel layer reaches low resistance apears under these conditions. Accordingly, the abnormal phenomenon of the FET is avoided, and yield can be improved. |
