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Planar Microcircuit With Resistor Diodes Formed in Localized Epitaxial Regions

IP.com Disclosure Number: IPCOM000075162D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Frantz, H: AUTHOR [+5]

Abstract

The chip surface area occupied by a given microcircuit can be reduced by forming the resistor and diode components thereof in localized epitaxial regions that extend vertically from underlying planar devices. Depending upon the conductivity type of the localized epitaxial regions and/or the semiconductor substrate on which the epitaxial regions are superimposed, resistor and/or diode structures are formed without requiring additional surface area allocation.

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Planar Microcircuit With Resistor Diodes Formed in Localized Epitaxial Regions

The chip surface area occupied by a given microcircuit can be reduced by forming the resistor and diode components thereof in localized epitaxial regions that extend vertically from underlying planar devices. Depending upon the conductivity type of the localized epitaxial regions and/or the semiconductor substrate on which the epitaxial regions are superimposed, resistor and/or diode structures are formed without requiring additional surface area allocation.

Referring to Drawing A, a planar transistor is formed in N-epitaxial layer 11 on P-substrate 10 by diffusing P-base region 12 and N+ emitter region 13 into the epitaxial layer. Layer 16 is an oxide layer which is selectively removed for the formation of localized P-epitaxial layers 14 and 15. Metallic contacts 1, 2, 3 and 4 complete the structure, which is represented by the functionally equivalent schematic diagram of Drawing B. Resistor R1 represents the resistivity of P- epitaxial region 15, which is located between terminal 2 and the base 13 of the planar transistor. Resistor R2 and the diode D represent the P-epitaxial region 14 and the N+ emitter 13 of the planar transistor.

Diode and/or resistor structures may be formed in the indicated manner where desired without commensurate increase in the required microcircuit surface area. The electrical characteristics of the resistors and diodes may be tailored in accordance with the...