| 摘要 |
1294515 Semiconductor devices WESTERN ELECTRIC CO Inc 15 Sept 1970 [15 Sept 1969] 43901/70 Heading H1K In a method of making a semiconductor device a mask comprising two layers of material having aligned apertures is formed on the surface of a semiconductor body 2, the aperture in the upper layer is enlarged so that border of the lower layer surrounding the aperture is exposed and ions are implanted into the body through the aperture in the lower layer and through the portion of the lower layer exposed by the upper layer. An N type Si body (11) is provided with a first masking layer (14) of silicon oxide by thermal oxidation or deposition, a second masking layer (15) of Al 2 O 3 or Si 3 N 4 by evaporation, sputtering or thermal decomposition, a third layer (16) of silicon oxide, and a photoresist layer (17). An aperture (18) in the photoresist allows the silicon oxide third layer (16) to be etched to form a mask for the etching of a corresponding aperture in the second masking layer (15) using hot phosphoric acid. The wafer is then etched in HF to completely remove the third layer and to etch an aperture in the silicon oxide first masking layer (14). The second masking layer 15 is then etched in hot phosphoric acid to reduce its thickness and increase the size of the aperture to provide a mask structure as shown in Fig. 1. B ions are then implanted with such an energy that they enter the silicon body through the exposed part of layer 14 to form a P type region 12, the junction 13 being passivated by layer 14. Layer 15 may be left in position or removed. The second masking layer (15) may be of a metal such as Cu, H 3 NO 4 -being a suitable etchant. Selective back sputtering may be used instead of etching to form apertures in the masking layers. Multiple masks may be provided by means of which a transistor structure may be fabricated by two successive ion implantations and a diffusion step, and such a device may form part of a junction isolated integrated circuit. |
