| 摘要 |
A monocrystalline semi-conductor element is deposited from a reaction gas containing a gaseous compound of the element on to a mono-crystalline semi-conductor carrier body doped to a resistivity not greater than 0.1 ohm cm., and heated to a temperature which is equal to or above that corresponding to the maximum deposition rate (Tm) and lies in the range in which the deposition rate decreases with increasing temperature for the particular reaction gas used. Preferably, Si is deposited on to a Si body from a gas containing SiHCl3, SiCl4, SiH2Cl2 or SiH3Cl. The body may be heated by passage of electric current, by placing it on a heated support, e.g. graphite, by H.F. induction heating, or by radiation from a source outside the vessel. The gaseous compound may be mixed with a reactive and/or non-reactive gas, e.g. H2 and Ar respectively. Tm depends upon the composition of the gas mixture: with 5 mole per cent SiHCl3 and 95 mole per cent H2, Tm is 1400 DEG C.; with 2+98 mole per cent respectively, Tm is 1100 DEG C. In the latter case operating temperatures of 1200 DEG and 1250 DEG C. are specified. The gas pressure may be 1 atm., and the flow rate 10 1./min. Selected areas of the body may be raised to a higher temperature, e.g. 1350 DEG C., by supplementary means, e.g. by optically concentrating light (e.g. wavelength less than 1 m ) from a laser source, in order to reduce the amount of material deposited on, or even to remove material from, those areas. The carrier body may be a disc, rod, or strip; the deposited layer may be of opposite conductivity to the carrier body and may have a sp. res. of 1-100 ohm cm. |
