| 摘要 |
PURPOSE:To contrive the uniformization of alloy reaction, reduction of contact resistance, and electrode short-circuit prevention by a method wherein one of substrate components is contained previously into an electrode before alloying heat treatment. CONSTITUTION:A source electrode 7 and a drain electrode 8 which contacts in ohmic manner with the GaAs substrate 1 are formed by superposing an Au layer 20 of approx. 4,000Angstrom , via an Ni layer 19 of the thickness approx. 1,500Angstrom , on a layer 18 of the thickness approx. 1,300Angstrom wherein Ga at approx. 2-3wt% (nearly the limit of solid solution) is contained to AuGe (12wt% Ge) and Au. Since Ga of substrate component is contained in the electrodes to the neighborhood of the limit of solid solution, the Ga does not infiltrate more from the substrate into the electrodes. Thereby, the sintering between the electrodes and the substrate does not generate, reaction is unified, electrode components do not infiltrate into the substrate, and accordingly short-circuit and poor withstand voltage do not occur. Since there is no variation of components of the substrate 1 in the electrode forming region, contact resistance is made low. |
