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Multibeam Method for Growing Large Grain Semiconductor Films

IP.com Disclosure Number: IPCOM000088155D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 3 page(s) / 83K

Publishing Venue

IBM

Related People

Ho, PS: AUTHOR [+2]

Abstract

Crystallization of large-grain semiconductor films by multiple power beam writing for solar cell applications is described herein.

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Multibeam Method for Growing Large Grain Semiconductor Films

Crystallization of large-grain semiconductor films by multiple power beam writing for solar cell applications is described herein.

For solar cell applications, there is a need for growing large-grain semiconductor films. Recently, in an in-situ transmission-electron-microscopy study of electron-beam induced crystallization of amorphous Ge films, it was observed that grains of size larger than a micron can be formed. The observed distributions of grain orientation and geometry can be correlated to the magnitude of the heat of transformation and the local temperature. The results can be explained by the idea that the grain size is mainly determined by the competing kinetic processes of grain growth and nucleation. Fig. 1 shows schematically the predicted temperature dependence for the growth rate and the nucleation rate of amorphous materials. Generally, there is critical temperature T(c) above which the growth rate is relatively high and the nucleation rate is so small, thus nucleation will not occur during crystallization.

A method is described herein for growing large-grain semiconductor films by using multiple power beams. The procedure is started by heating the film uniformly to an initial temperature T(i) of about 500 Degrees C where the nucleation rate is low so only a few grains are nucleated. Then, by applying multiple power beams on the film to raise rapidly the local temperature T(f) where the rate of growth is dominant, large grains can grow within the influence of the power beam. Power beams are used for raising the local temperature and a multiple number of them are used so that...