Process for the production of a crystallised semiconductor material

• Main Authors: PALTRIER, M. SYLVAIN, MIGUET, M. THIERRY
• Format: Patent
• Language: English; French; German
• Published: 07.09.2011
• Subjects: AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUSPOLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR; CHEMISTRY; CRYSTAL GROWTH; METALLURGY; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; REFINING BY ZONE-MELTING OF MATERIAL; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITHDEFINED STRUCTURE; SINGLE-CRYSTAL-GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL ORUNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL

The process comprises synthesizing a crystallized compound semiconductor material of type II-VI material by melting and reacting between each of its constituents, crystallizing the material in liquid form by cooling a sealed ampoule (1) according to a specified temperature gradient, increasing the proportion of a filler of one of the constituents of the material beyond the stoichiometric proportions of the material, and subjecting the entire ampoule to a temperature greater than or equal to the melting temperature of the semiconductor material. The process comprises synthesizing a crystallized compound semiconductor material of type II-VI material by melting and reacting between each of its constituents, crystallizing the material in liquid form by cooling a sealed ampoule (1) according to a specified temperature gradient, increasing the proportion of a filler of one of the constituents of the material beyond the stoichiometric proportions of the material, subjecting the entire ampoule to a temperature greater than or equal to the melting temperature of the semiconductor material, inducing the effective fusion of the filler and the reaction of its constituents between them when in liquid form and the transformation of the excess constituent into dry steam, subjecting the ampoule to a low temperature gradient and to a progressive lowering of the temperature, specific to induce the crystallization of the compound semiconductor material resulting when in liquid form, in stoichiometric proportion, the excess constituent residing in the form of dry steam, subjecting the part of the ampoule away from the crystallized semiconductor materials to a drop of temperature capable of modifying the steam pressure system of the excess constituent to supply the constituent to a saturation steam system, and cooling the material to room temperature. The constituents are placed in elemental form constituting the filler in the ampoule. The quantity of the excess constituent is at most equal to the quantity corresponding to the establishment at a temperature greater than or equal to the melting temperature of the compound semiconductor material to be prepared and at high pressure of the constituent, then in the form of dry steam, less than the pressure of the bursting of the ampoule, determined by application of Mariotte law. The sealed ampoule comprises two zones having a zone of larger diameter for receiving the filler to be crystallized, a zone of smaller diameter in continuity with the zone of largest diameter subjected to the localized management of temperature and consequently in changing of nature dry steam having saturation steam and the steam from the excess constituent. Ce procédé pour la réalisation d'un matériau semi-conducteur composé cristallisé consiste à synthétiser ledit matériau par fusion et réaction entre eux de ses constituants, lesdits constituants étant placés sous forme élémentaire constituant une charge dans une ampoule scellée (1), puis à cristalliser le matériau semi-conducteur résultant de cette opération alors sous forme liquide par refroidissement de l'ampoule selon un gradient thermique déterminé. Ce procédé consiste en outre : - à augmenter au sein de la charge la proportion de l'un des constituants dudit matériau au delà des proportions stoechiométriques du matériau semi-conducteur à synthétiser, définissant un excès de l'un desdits constituants ; - à soumettre l'intégralité de l'ampoule scellée à une température supérieure ou égale à la température de fusion du matériau semi-conducteur à synthétiser ; - à soumettre alors l'ampoule à un gradient faible de température et à un abaissement progressif de la température, propres à induire la cristallisation du matériau semi-conducteur composé en résultant, alors sous forme liquide, en proportion stoechiométrique ; - puis, à soumettre la partie de l'ampoule hors le lieu de présence du matériau semi-conducteur cristallisé, à un abaissement de température apte à modifier le régime de pression de vapeur du constituant en excès, afin de l'amener à un régime de vapeur saturante ; - et enfin, à refroidir l'ensemble jusqu'à température ambiante.