Process for the preparation of monocrystalline semiconducting elements

摘要

A monocrystalline semi-conductor element is deposited from a gas on to a rod-shaped carrier of the same element heated inductively (at Ta) below the melting point of the element (Ts) and above the temperature at which the rate of deposition is a maximum (Tmax); the gas being selected so that, for a certain range of increasing temperature, the rate of decomposition decreases (see Fig. 1). The semi-conductor element may be Si, Ge or B. The gaseous semi-conductor compound may be a wholly or partially halogenated hydride, e.g. SiCl4, SiHCl3 or SiH2Cl2, used in amount up to 5 mole per cent, and diluted with H2; each has a different Tmax (with 2 and 5 mole per cent SiHCl3, Tmax is given as 1100 DEG and 1400 DEG C. resp.). A doping element, or its compound with halogen or hydrogen may be included in the gas. Experimental details are as given in Specification 880,559. In Fig. 2, H2 is passed through vessel 8 containing liquid SiHCl3, and the mixture of 2% SiHCl3 and 98% H2 passes through inlet 4 into quartz vessel 1 containing carrier 3 heated by H.F./A.C. induction coils 6 to 1250 DEG C. The carrier may be preheated in H2. Specifications 809,250 and 908,373 also are referred to.ALSO: A monocrystalline semi-conductor element is deposited from a gas on to a rod-shaped carrier of the same element heated inductively (at Ta) below the melting point of the element Ts and above the temperature at which the rate of deposition is a maximum (Tmax); the gas being selected so that, for a certain range of increasing temperature, the rate of decomposition decreases (see Fig. 1). The semi-conductor element may be Si, Ge or B. The gaseous semi-conductor compound may be a wholly or partially halogenated hydride, e.g. SiCl4, SiHCl3 or SiH2Cl2, used in amount up to 5 mole per cent and diluted with H2; each has a different Tmax (with 2 and 5 mole per cent SiHCl3, Tmax is given as 1100 DEG C. and 1400 DEG C. respectively). A doping element, or its compound with halogen or hydrogen, may be included in the gas. Experimental details are as given in Specification 880,559. In Fig. 2, H2 is passed through vessel 8 containing liquid SiHCl3, and the mixture of 2% SiHCl2 and 98% H2 passes through inlet 4 into quartz vessel 1 containing carrier 3 heated by H.F./A.C. induction coils 6 to 1250 DEG C. The carrier may be preheated in H2. Specifications 809,250 and 908,373 also are referred to.