Method of electrolessly plating alloys

Claim 2

METHOD OF ELECTROLESSLY PLATING A DOPED GOLD ALLOY CONTACT ONTO THE SURFACE OF A SEMICONDUCTOR SUBSTRATE INCLUDING ELEMENTS FROM THE GROUP III-V ELEMENTS OR MIXED COMPOUNDS OF THESE ELEMENTS, COMPRISING THE STEPS OF : MIXING A GOLD CHLORIDE SOLUTION WITH A SOLUTION OF ZINC CHLORIDE IN THE RATIO OF 1:5 GRAMS TO 3.0 GRAMS CRYSTALLINE GOLD CHLORIDE TO 400 MILLILETERS TO 200 MILLIGRAMS ZINC FOR A SOLUTION OF 50 MILLIETERS; AND IMMERSING THE SEMICONDUCTOR SUBSTRATE IN SAID MIXED SOLUTION FOR A FIXED PERIOD OF TIME UNTIL A DESIRED THICKNESS OF DOPED GOLD ALLOY HAS BEEN PLATED ONTO SAID SUBSTRATE, THEREBY PLATING ZINC DOPED GOLD ONTO SAID SEMICONDUCTOR SUBSTRATE AT AN INITIAL RATE OF 2,000 TO 2,500 ANGSTROMS IN APPROXIMATELY 2-3 MINUTES AT ROOM TEMPERATURE.

Claim 3

Method of electrolessly plating a doped gold alloy contact onto the surface of a semiconductor substrate including elements from the group III- V elements or mixed compounds of these elements, comprising the steps of: mixing a gold chloride solution with crystalline stannous chloride in the ratio of approximately 1.5 grams of crystalline gold chloride to approximately 100 milligrams of crystalline stannous chloride for a 50 milliliter solution; adding a few millileters of hydrochloric acid to dissolve any resultant precipitate; and immersing the substrate in said mixed solution for a fixed period of time until a desired thickness of alloy has been plated onto said substrate, thereby plating tin doped gold onto said semiconductor substrate at an initial rate of 2,000 to 2, 500 angstroms in approximately 2-3 minutes at room temperature.

Claim 4

Method of electrolessly plating a doped gold alloy contact onto the surface of a semiconductor substrate including elements from the group III- V elements or mixed compounds of these elements, comprising the steps of: mixing a gold chloride solution with crystalline stannous chloride in the ratio of approximately 1.5 grams of crystalline gold chloride to approximately 100 milligrams of crystalline stannous chloride for a 50 milliliter solution; adding a few millileters of hydrochloric acid to dissolve any resultant precipitate; and immersing the substrate in said mixed solution for a fixed period of time until a desired thickness of alloy has been plated onto said substrate, thereby plating tin doped gold onto said semiconductor substrate at an initial rate of 2,000 to 2, 500 angstroms in approximately 2-3 minutes at room temperature.

Claim 5

Method as in claim 2 wherein: the step of adding hydrochloric acid is omitted and in its place is substituted the step of filtering off any resultant precipitate.