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Alloying Contacts on Semiconductor Bodies

IP.com Disclosure Number: IPCOM000096390D
Original Publication Date: 1963-May-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Leff, J: AUTHOR

Abstract

Ohmic and rectifying contacts of many different metals can be alloyed with semiconductor bodies by using sodium chloride as a covering medium or boat. The drawings show some of the many possibilities of an evaporated salt boat.

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Alloying Contacts on Semiconductor Bodies

Ohmic and rectifying contacts of many different metals can be alloyed with semiconductor bodies by using sodium chloride as a covering medium or boat. The drawings show some of the many possibilities of an evaporated salt boat.

Metal stripe 11 of a readily wetting or a poorly wetting metal is deposited on semiconductor wafer 10 as by evaporating through a hole in an apertured mask, not shown. That mask is removed and is replaced by one with a larger opening in it. Then, layer or boat 12 of sodium chloride is evaporated over stripe 11 (B). The thickness of boat 12 is preferably less than that of the metal stripe. Then, metal layer 13 is evaporated on the upper surface of the assembly (C). Next, second layer or confining boat 14 of sodium chloride is evaporated on the upper surface of the assembly to form the unit shown in D. This unit can now be alloyed by introducing it into an alloying furnace preferably held at a temperature below the 801 degrees C melting point of the salt. Ohmic or rectifying contacts can be formed on the semiconductor body 10 depending upon the metals employed, the conductivity-determining impurities in it and the conductivity type of the semiconductor body.

After alloying, the unit shown in D is inserted in a solvent for the salt such as water or dilute hydrofluoric acid. Salt boat 14 is first dissolved and then the solvent penetrates the thin and partially discontinuous regions 15, 15 of the metal ...