Browse Prior Art Database

Semiconductor Resistor

IP.com Disclosure Number: IPCOM000094111D
Original Publication Date: 1966-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 80K

Publishing Venue

IBM

Related People

Gates, HR: AUTHOR

Abstract

This semiconductor resistor is useful for high-density integrated circuits.

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Semiconductor Resistor

This semiconductor resistor is useful for high-density integrated circuits.

In drawing A1 substrate 10, preferably of P/-/ type conductivity, is used as a starting material. An N/+/ region 12 is formed in a surface portion of substrate 10 by suitable diffusion techniques. Such occurs after an opening is formed in an oxide layer by conventional photolithographic masking and etching techniques.

Subsequently, as in drawing A2, region 14 of N-type material is epitaxially grown on substrate 10. It is during this epitaxial growth process that region 12 outdiffuses into region 14. P/+/ isolation regions 16, drawing A3, are formed preferably by diffusion serve to isolate region 14.

P-type base region 18 is formed in the epitaxially grown region 14 by standard diffusion techniques as in drawing A4. N/+/ regions 20 and 22 are formed by diffusion in the surface of 14 as in drawing A5.

Subsequently, ohmic contacts 31...34 are respectively provided to region 20, one portion of region 18, another portion of region 18, ad to region 22. As shown in drawings A6 and B, more than one electrical resistance is formed by regions 18, 14, and 12. This arrangement permits a diffused resistor of one type conductivity to be located over a resistor formed by a semiconductor region of the opposite conductivity. Thus the total surface area required for integrated circuit resistors is reduced. The important consideration is that the PN diode separating the two resistors...