METHOD OF SUPPLYING GASEOUS HYDROGEN IN GROWTH OF SILICON SINGLE CRYSTAL

PROBLEM TO BE SOLVED: To enhance the effect of mixing of gaseous hydrogen by making mixing of high concentration gaseous hydrogen possible while securing safety. SOLUTION: When a silicon single crystal is grown by a CZ method in an inert atmosphere containing hydrogen, gaseous hydrogen is supplied into a single crystal pulling furnace in a concentration not higher than the concentration mentioned below. When the dilution limit of the mixed gas to detonation is defined as K1and the air composition on the side BC showing the volume ratio of gaseous oxygen and inert gas is defined as D in the triangle diagram of a ternary component system having apexes A, B, and C corresponding to gaseous hydrogen, gaseous oxygen and the inert gas, respectively, gaseous hydrogen is supplied in a concentration not higher than the hydrogen gas concentration shown by the intersecting point S1where a straight line from D to K1intersects with the side CA showing the volume ratio of the inert gas and gaseous hydrogen. When the detonation range on the side AB showing the volume ratio of gaseous hydrogen and the gaseous oxygen is set to be L1to L1', and the detonation range on the straight line DA connecting the air composition D on the side BC showing the volume ratio of gaseous oxygen and the inert gas and the apex A is set to be M1to M1', the dilution limit K1of the mixed gas to detonation is given by the intersecting point where the straight line L1M1intersects with the straight line L1'M1'. COPYRIGHT: (C)2004,JPO&NCIPI