GB1297315A - - Google Patents

Abstract

1297315 Epitaxial growth LICENTIA PATENT-VERWALTUNGS GmbH 9 Sept 1970 [11 Sept 1969] 43180/70 Heading B1S A method of producing epitaxial growth comprises the steps of:- (1) brining a melt from which an epitaxial growth layer is to be precipitated into contact with an excess of the substance from which the layer is to be made and simultaneously heating the melt until a saturated solution of the said substance in the melt is produced (2) separating the saturated melt from the supply of the said substance and bringing it into contact with the substrate on which the epitaxial layer is to be produced, (3) cooling the melt continuously in order to deposit a layer of the said substance on to the substrate, and then separating the melt from the substrate. Two embodiments of apparatus suitable for performing the process of the invention are disclosed, one being illustrated in Figs. 1-5. In Fig. I the melt is introduced into the compartment 1.3 and the substance to be precipitated is introduced into the same compartment via screw stopper 1.6. The substrate 1.7 is wedged in the recess 1.3. When the melt and layer-forming substance have been introduced they are heated as in Fig. 2, the apparatus is then invented as in Fig. 3 to remove the melt from the substance, the melt can now be heated to raise the temperature by a further 5 to 10‹C. The melt is then transferred by means of rod 4.8 to the position shown in Fig. 4. The melt may be maintained at the elevated temperature for a short while to allow removal of some of the substrate surface by thermal etching. The melt is then cooled and an epitaxial layer is formed on the substrate. the melt and substrate may then be separated by inversion of the apparatus as in Fig. 5 and the process repeated if required. In the embodiment described the melt is gallium and the epitaxial layer composed of gallium arsenide. The other embodiment described operates in a similar fashion, contact and separation being achieved, however, by rotation of a G-shaped crucible.