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Graded Concentration Semiconductor

IP.com Disclosure Number: IPCOM000098389D
Original Publication Date: 1960-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Anderson, RL: AUTHOR [+3]

Abstract

A graded base semiconductor element is produced in which a high concentration of conductivity type determining impurities is provided in one area of the element and a lower concentration in other areas. This is accomplished by a vapor deposition process. It employs pyrolytic decomposition of a compound of a halogen and a semiconductor in which the conductivity type determining impurity exhibits a delay in reaching a concentration equilibrium when introduced into the vapor. This delay is capable of producing a graded impurity density in the semiconductor material being deposited on the substrate.

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Graded Concentration Semiconductor

A graded base semiconductor element is produced in which a high concentration of conductivity type determining impurities is provided in one area of the element and a lower concentration in other areas. This is accomplished by a vapor deposition process. It employs pyrolytic decomposition of a compound of a halogen and a semiconductor in which the conductivity type determining impurity exhibits a delay in reaching a concentration equilibrium when introduced into the vapor. This delay is capable of producing a graded impurity density in the semiconductor material being deposited on the substrate.

The method is illustrated for a PN junction using arsenic or phosphorus as a donor or N conductivity type determining impurity and gallium or boron as an acceptor or P conductivity type impurity.

A monocrystalline substrate 10, a first source of semiconductor material 11 containing a quantity of N conductive type determining impurity, and a second source of semiconductor material 12 containing a P conductive type determining impurity are positioned in a quartz tube 13. Heating elements 14 and 15 surround the positions of the materials 11 and 12, respectively. A heating element 16 surrounds the substrate 10.

The temperature within the tube 13 is raised by applying power to heating elements 14, 15 and 16 to a point where a transport element introduced into the tube and the materials 11 and 12 combine in the form of a vaporized compound
17....