| 摘要 |
PURPOSE:To obtain a polycrystalline Si thin film having a large crystal grain diameter and high orientation by a method wherein the semiconductor thin film on a predetermined substrate is changed to be amorphous by implantation of a predetermined ion, then changed to a thin film of a predetermined film thickness, and heat-treated. CONSTITUTION:A polycrystalline Si thin film 3 having crystal grains 3a is deposited on the SiO2 film 2 on a quartz substrate 1. Then, Si<+> is improved thereby to change the polycrystalline Si 3 to an amorphous Si 4. After cleansing with a solution of H2O:H2O:NH3=7:2:1, the amorphous Si film 4 is lightly etched with a solution of H2O:Sol=15:1 thereby to be changed to a thin film of about 200Angstrom , and an SiO2 film 5 is deposited thereon by the low-pressure CVD method. Annealed in N2 at 1,000 deg.C, a polycrystalline Si film 6 can be obtained, the crystal grains 6a of which are extremely large and have a plane orientation for minimum surface energy (100). Thereafter, the SiO2 film 5 is removed. With this polycrystalline Si thin film, a thin film semiconductor device having a good characteristic can be obtained. |
