GB1345367A - Growing crystals upon a substrate - Google Patents

Abstract

1345367 Crystallizing apparatus; epitaxial deposition WESTERN ELECTRIC CO Inc 19 April 1971 [16 March 1970] 24031/71 Headings B1G and B1S [Also in Division C1] An apparatus provides a four step cycle for growing a crystal on a substrate 44, from a melt 45 in a compartment 61, by cooling the substrate with heat exchanger 77. A slider 51 and boat 59 of pure graphite are loaded with a source mixture 54 for doping the melt, and a melt mixture 62, covered by a lid 65. The boat is slid on to a base member 41 carrying the substrate 44 and after positioning two stop bars 50, 55, the assembly is placed in a furnace 74 so that the substrate 44 overlies heat exchanger 77. On moving slider 51, inwardly, Fig. 4B, both the mixture 54, in slider recess 56 and the substrate 44 are sealed in, to prevent degradation, while the melt mixture 62 is fused. In the 4C position, the melt 45 is saturated with the mixture 54 before being moved into contact with the substrate 44 (Fig. 4D). Crystal growth takes place, as heat exchanger 77 is supplied with coolant gas, in order to establish a vertical temperature gradient in melt 45. In order to stop crystal growth, the slider 51 is pulled back to the 4E position, thus depositing part of the melt 45 in base compartment 47. The apparatus may be used for producing a p-type epitaxial layer of Ga P on a p-type Ga P substrate, from a Ga solution doped with n and O 2 .