Browse Prior Art Database

Monitoring Diameter of Semiconductor Crystals During Automated Growth

IP.com Disclosure Number: IPCOM000086242D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Hull, EM: AUTHOR [+6]

Abstract

U. S. Patent 3,621,213 describes a system for automated growth of semiconductor crystals, In addition to the parameters monitored and controlled by the computer control system during crystal growth, D. S. Coburn et al, IBM Technical Disclosure Bulletin, Vol. 15, No. 4, September 1972, pp. 1334 - 1335, teach a further advantage may be achieved by also automatically monitoring the crystal diameter, particularly during some of the initial stages of growth.

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Monitoring Diameter of Semiconductor Crystals During Automated Growth

U. S. Patent 3,621,213 describes a system for automated growth of semiconductor crystals, In addition to the parameters monitored and controlled by the computer control system during crystal growth, D. S. Coburn et al, IBM Technical Disclosure Bulletin, Vol. 15, No. 4, September 1972, pp. 1334 - 1335, teach a further advantage may be achieved by also automatically monitoring the crystal diameter, particularly during some of the initial stages of growth.

The automated crystal growth process is basically divided into growth sections including seeding, necking, shouldering, round over and, finally, separation from the melt. The published system provides for monitoring crystal diameter from the seeding stage, until the crystal assumes the uniform cylindrical diameter of its main body.

It accomplishes this when an IR-TV monitor is fixed to a given point and monitors the surface of the crystal as the crystal is drawn past this point. It is used primarily to measure the crystal diameter during the seeding, neck-in and shouldering phases of crystal growth.

The present system provides for complete diameter monitoring during the growth of the crystal through all stages.

With reference to Fig. 1, the apparatus which is generally similar to that described in the patent and publication is shown. The system program is shown in Fig. 2. Diameter readings are read and interpreted from video voltage scan across...