GB1075387A - Improvements in semicuoductor device making - Google Patents

Abstract

An epitaxial layer is produced on the exposed parts of a semi-conductor source masked with silicon dioxide by placing a source body of semi-conductor material in confronting relationship with the substrate and performing a transport reaction using iodine vapour. The process is performed in a reaction vessel (2, Fig. 1, not shown), in which a plurality of masked silicon substrates (32) rest on a support (22) which can be heated. Each substrate is surrounded by a quartz spacer (50, Fig. 3, not shown), which has apertures (52) to allow the entry of gases. A silicon source body (42), which may be of polycrystalline material, lies on top of each of the spacers (50). The apparatus is purged with argon and then evacuated. The substrates are heated to about 1100 DEG C., the source bodies being about 100 DEG C. cooler, and iodine vapour is admitted. Silicon is removed from the source bodies and epitaxially deposited on the exposed areas of the substrates. The heater is then de-energized, the iodine supply shut off, and the apparatus again purged with argon. The production of diodes and transistors by transport of doped layers is described (see Division H1). The semi-conductor material may also be germanium, indium antimonide, or gallium arsenide, and in the case of compounds an atmosphere of the more volatile component may be provided to help prevent decomposition of the semi-conductor compound.