| 摘要 |
PURPOSE:To enhance the workability of an MOS transistor and to enable to cut down the cost thereof by a method wherein, when a semiconductor layer is deposited on the insulative substrate, first and second ion implanted layers are respectively formed in the bottom surface and upper surface of the semiconductor layer and the MOS transistor of this type is constituted, the mask to be used is limited to one kind only and the resist pattern to be provided under the mask is replaced. CONSTITUTION:An Si layer 22 is deposited on a sapphire substrate 21, field insulating films 23 are formed at the end parts of the Si layer 22, a first ion implanted layer 28, which is used for reducing the leakage current from the back channel of the element, is formed in the bottom surface of the layer 22 and a second ion implanted layer 31 for threshold voltage control, which is located in the surface of the layer 22, is formed. For forming these ion implanted layers 28 and 31, a masking material 26 to be provided on the layer 22 is constituted of a glass substrate 24 having a Cr film 25 to be formed in the prescribed pattern on its surface, a resist pattern 27 having an opening to correspond to the layer 28 is provided under the masking material 26, an ion-implantation, by which the peak is generated in the interface between the substrate 21 and the layer 22, is performed and the layer 28 is formed. After that, the resist pattern 27 is removed, a gate oxide film 29 is coated on the surface of the layer 22, a resist pattern 30 of the same type as the resist pattern 27 is provided and the layer 31 is made to grow under the film 29 using low-acceleration ions.
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