| 摘要 |
PURPOSE:To deposit boron on an silicon wafer by using wafer-shaped thermally decomposed boron nitride (P-BN) in place of a BN wafer. CONSTITUTION:Recessed spot facings 2' are formed to P-BN wafers 2, and the wafers are fixed. Windows are bored previously at positions where boron must be deposited through the formation 3 of an oxide film and a photoetching process in an Si wafer first. The surface on which boron must be deposited of the Si wafer 1 and the surfaces of the P-BN wafers are brought into contact mutually, and charged into a furnace at 700-1000 deg.C. Only an inert gas or the mixed gas of the inert gas and oxygen gas and the mixed gas of inert gas: oxygen gas:hydrogen chloride gas=5:5:l (flow ratios) are flowed for ten min as a gas. The Si wafer is heated by the same furnace for thirty min or more only by the inert gas. Accordingly, since boron can be deposited by a high-purity impurity source, defects in a diffusion are reduced largely, and attention need not be paid particularly for storing P-BN, and wet washing is enabled even in the pretreatment of P-BN and the wafers can be brought to a clean state at all times.
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