Abstract: In order to effectively remove gas molecules of a by-product in a chemical reaction in a solution so as to achieve high efficiency, high rate, and uniformity of the chemical reaction in the solution and in order to realize formation of a semiconductor substrate applicable to production of SOI structure and realize formation of a semiconductor substrate in which a light-emitting element or a gas sensor can be formed, on the basis of an inexpensive silicon substrate, the chemical reaction is performed while the concentration of a gas dissolved in a reaction solution in a reaction vessel is always controlled to be not more than the solubility thereof during the reaction.

Abstract: A semiconductor substrate adapted to giga-scale integration (GSI) comprises a support, at least the surface of which is made of semiconductor, an electroconductive material layer, an insulating layer and a semiconductor layer arranged sequentially in the above order. The electroconductive material layer has at least in part thereof an electroconductive reacted layer obtained by causing two metals, a metal and a semiconductor, a metal and a metal-semiconductor compound, a semiconductor and a metal-semiconductor compound, or two metal-semiconductor compounds to react each other. An electroconductive reaction terminating layer that is made of a material that does not react with the reacted layer is arranged between the reacted layer and the insulating layer or the support.