| 摘要 |
PURPOSE:To prevent the heat deterioration of an ohmic electrode even through heat treatment for a prolonged term at a high temperature of 400 deg.C or higher by using a laminate, in which an Au-Ge layer, a W layer, an Ni layer and an Au layer are laminated in succession, as the ohmic electrode to an N type conductive layer formed to a gallium-arsenic crystal substrate. CONSTITUTION:N<+> layers 2 and an N layer 3 are formed onto a semi-insulating GaAs substrate 1 while using Si as an ion source. SiO2 films 4 are employed as surface protective films, and the N<+> layers 2 and the N layer 3 are activated in a H2 gas atmosphere. Ohmic electrode holes are shaped, the SiO2 films 4 are removed, and first layer AuGe layers 5, second layer W layers 6, third layer Ni layers 7 and fourth layer Au layers 8 are formed continuously. Ohmic electrode patterns are shaped, and ohmic contacts are obtained to the N<+> layers 2 through heat treatment in a N2 gas atmosphere. A gate electrode 9 is formed, a FET is manufactured, a PSG film 10 is applied as an inter-layer insulating film, contact holes are bored to the PSG film 10, and wiring metals 11 are formed. |
