| 摘要 |
PURPOSE:To obtain a highly reliable ohmic electrode having a smooth electrode surface and low contact resistance without alloying operation by depositing a metal film on the germanium thin film having a doner impurity introduced therein. CONSTITUTION:Si<+> is selectively implanted into a semi-insulating GaAs substrate 1, thereby to form a surface conductive layer region 3. Thereafter, a Ge thin film 4 is deposited on the ohmic electrode forming region. An arsenic-doped silicon dioxide (ASG) film 5 is deposited on the entire surface of the substrate 1 and the heat treatment is performed thereon in the atmosphere of Ar gas or the like. The Ge thin film 4 and the GaAs substrate 1 react each other and the Ge thin film 4 is doped with As at a high density since the ASG film 5 is employed as the diffusion source, whereby Si<+> implanted into the GaAs substrate 1 is activated as well. A window for the electrode is formed in the ASG film 5 and then a metal film 7 is deposited by evaporation of Ti. The impurity concentration in the Ge thin film 4 shall be 10<19>cm<-3> or more and the specific resistance of the Ge thin film 4 itself is decreased, thereby to lessen the contact resistance between the thin film 4 and the metal film 7. |
