Clad molybdenum disks for alloyed diode
AssigneeInternational Rectifier Corporation
InventorsJoseph Wislocky, Thomas J. Roach
Life of this patent
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Abstract
An alloyed diode is formed of a silicon wafer which is sandwiched between two pre-clad molybdenum disks. The upper molybdenum disk is clad on the side facing the silicon wafer with a thin aluminum foil and is clad on its outer surface with a nickel foil. The bottom molybdenum is clad with a solder foil of silver containing small amounts of germanium, copper and arsenic on the surface facing the silicon and is clad with nickel on its opposite surface. The three parts are stacked atop one another and placed in an alloying furnace to form a completed semiconductor wafer with solderable electrodes on opposite sides.
Claims6
An alloyed diode device comprising a silicon water;
- first and second pre-clad expansion plates of metal having respective first and second parallel surfaces and having respective coefficients of expansion similar to that of said silicon;
- said first expansion plate having first and second solder foils pre-clad thereto and extending over the full areas of said first and second surfaces respectively of said first expansion plate;
- said second expansion plate having a third solder foil pre-clad to said first surface thereof and a fourth foil of a predetermined impurity type for producing a rectifying junction in said silicon wafer pre-clad to said second surface of said second plate;
- said third and fourth foils extending over the full areas of said first and second surfaces respectively of said second expansion plate;
- said silicon wafer disposed between said first and second pre-clad expansion plates;
- said first solder foil of said first expansion plate soldering said first expansion plate to one surface of said silicon wafer;
- said fourth foil being alloyed into the opposite surface of said silicon wafer.
Dependencies are inferred from the claim text.