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Passivation of Alloy Junctions

IP.com Disclosure Number: IPCOM000096192D
Original Publication Date: 1963-Jan-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Stehney, TG: AUTHOR

Abstract

An alloy junction in a semiconductor device can be given the same passivation properties as a diffused junction. Semiconductor starting wafer 10 has grown upon or suitably applied to it an impervious film 11 of a material such as silicon dioxide. Then a ring of the film is removed so as to expose annular surface portion 12 of wafer 10. By a diffusion operation, an impurity is diffused deeply into portion 12 to form annular region 13 of a conductivity type opposite that of wafer 10. Junction 14 which comes to the surface of the semiconductor is not exposed, since it is covered by oxide film 11.

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Passivation of Alloy Junctions

An alloy junction in a semiconductor device can be given the same passivation properties as a diffused junction. Semiconductor starting wafer 10 has grown upon or suitably applied to it an impervious film 11 of a material such as silicon dioxide. Then a ring of the film is removed so as to expose annular surface portion 12 of wafer 10. By a diffusion operation, an impurity is diffused deeply into portion 12 to form annular region 13 of a conductivity type opposite that of wafer 10. Junction 14 which comes to the surface of the semiconductor is not exposed, since it is covered by oxide film 11.

Next, the central patch of silicon dioxide is removed by a selective etching operation to expose more of the top surface 15 of wafer 10. Then pellet 16 of an impurity of a conductivity type opposite that of wafer 10 is alloyed with surface 15 so that it also makes electrical engagement with annular region 13. Terminals (not shown) can now be applied to the device.

This technique produces an abrupt alloy junction. Such is characterized by its good injection and heat transfer properties and also the passivation properties of a good diffused junction. Breakdown occurs in the bulk of the semiconductor material rather than at its surface.

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