Method for producing semiconductor films on semiconductor substrates

摘要

In a process of coating a semi-conductor substrate such as silicon with a layer of semi-conductor material such as silicon, the semi-conductor substrate is mounted at least 10 mms. from a semi-conductor source in an atmosphere of a halide of the semi-conductor at a pressure of 10-1 to 10-6 mms.-Hg and the substrate and source are heated so that the substrate is maintained at least 20 DEG C. below the source temperature. Preferably, the respective temperatures are 1000-1180 DEG C and 1200-1350 DEG C The halide is preferably the tetrachloride of silicon; mixed halides of the constituents may be used in the case of a binary semi-conductor. The halide is mixed with hydrogen and the atmosphere should contain at least 10% by volume of the halides. As shown in the Figure, a silicon substrate 10 is mounted in a reaction chamber 12 and supported above a pedestal 11 which acts as the semi-conductor source. Heating is effected by R.F. coil 27, hydrogen is supplied from 16, the tetrachloride from bulb 21 via cold store 26 and the system is evacuated to the required pressure.ALSO: In a process of coating a semi-conductor substrate such as silicon or germanium with a layer of semi-conductor material such as silicon or germanium, the semi-conductor substrate is mounted at least 10 mms. from a semi-conductor source in an atmosphere of a halide of the semi-conductor at a pressure of 10-1-10-6 mm.s-Hg. and the substrate and source are heated so that the substrate is maintained at least 20 DEG C. below the source temperature. With a silicon substrate and source the respective temperatures are 1000-1180 DEG C. and 1200-1350 DEG C. and in the case of germanium the substrate is at 400-680 DEG C. and the source at 700-900 DEG C. The halide is preferably the tetrachloride of silicon or germanium or mixed halides of the constituents may be used in the case of a binary semi-conductor. The halide is mixed with hydrogen and the atmosphere should contain at least 10% by volume of the halides. As shown in the Figure, a silicon or germanium substrate 10 is mounted in a reaction chamber 12 and supported above a pedestal 11 which acts as the semi-conductor source. Heating is effected by R.F. coil 27, hydrogen is supplied from 16, the tetrachloride from bulb 21 via cold store 26 and the system is evacuated to the required pressure.