| 摘要 |
PURPOSE:To obtain a TiO2 reflection preventing film by a method wherein a substrate on which a photo-electromotive force junction plain is formed is immersed in a solution which contains Ti(OR)4 or TiCl4 and is lifted up at a required speed and is treated by heat. CONSTITUTION:An Si substrate on which a photo-electromotive force junction plain is formed is immersed in a solution of ethanol and ethyl acetate which contains 3.4% Ti(OC3H7)4 and is lifted up at a speed of 2.5mm./sec., so that the substrate is covered by a thin film of TiO2. The substrate is then burnt at a temperature not less than 300 deg.C. If the burning temperature is less than 300 deg.C the reflection preventing film will be darkened and if it is more than 1,100 deg.C a silver electrode will melt. The strength and adhesion of the film are significantly increased by the heat treatment. The thickness of the TiO2 film is determined by the lifting speed and the density of Ti(OR)4. The film thickness d which makes the reflection index minimum when a wavelength lambda0 is nearly 500nm is calculated by a formula nd=lambda0/4, where n is a refractive index, thus d=550-800Angstrom is most preferable. With the above method, a uniform reflection preventing layer can be obtained very easily at low cost by controlling the film thickness. |
