| 摘要 |
PURPOSE:To easily form an ohmic electrode having low contact resistance by a method wherein an ohmic electrode material is laminated on the side face and the bottom face of the groove on the inverted trapezoidal cross-section exposing of a conductive layer. CONSTITUTION:Negative type resist 4 is coated on a semiconductor substrate. A resist pattern 5 having an overhang part 6 protruded in bill-shaped eaves is formed by performing a far ultraviolet ray exposure in the irradiation dose of one-half of the ordinary irradiation dose and by conducting a developing process. An etching is performed using an Ar ion beam 7 in the extent wherein the beam penetrates a GaAs layer 3 containing no impurity but is penetrates an N-GaAs layer 2. A resist pattern 5 is widely perforated slowly by performing an etching on an overhang part 6, and a groove 8 having an inverted trapezoidal cross-section in formed on the semiconductor substrate. When ohmic electrode materials are vapor-deposited in the order of AuGe, Ni and Au, they are vapor- deposited as far as to the side face of the groove 8. An N<+>GeAs layer 11, whereon high density Ge is diffused, is formed by removing the resist pattern 5 and by performing a heat treatment. |
