Si単結晶の溶解
1960 年 29 巻 5 号 p. 296-302
詳細
1960 年 29 巻 5 号 p. 296-302
The rates of dissolution in normal and tangential directions to (111) surface of silicon single crystal are observed under various conditions in order to find out the relation between the geometrical forms of dissolved surfaces and the rates of dissolution in the two directions. Si specimens used are N type discs of approximately 0.3, 4 and 100 Ω•cm. The principal solutions used are composed of HNO3, HF, and H2O or NaOH and H2O. Many additional substances, for example, CH3COOH, HCl, H2SO4, H3PO4, CrO3, Br2, AgNO3, Hg2(NO3)2, Hg(NO3)2, Au(NO3)3HNO3 Pb(NO3)2 and NaNO2 are used. Experiments under special conditions such as irradiation or interruption of light were not undertaken. The rates of dissolution in the two directions and the ratio of the rates are given as functions of temperature and composition of the solution. The value of this ratio corresponds to that of tan θ given in YAMAMOTO'S work on the formation of etch pits on crystals. In the range studied, maximum values of θ are about 50° in the system HNO3-HF-H2O and about 88° in the system NaOH-H2O. It is found that the value of θ has a close relation to the geometrical form (microstructure) of dissolved (111) surface.
