| 摘要 |
1421212 Semi-conductor devices PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 5 April 1973 [8 April 19.72] 16310/73 Heading H1K In a method of making, for example, integrated circuits in which inset regions of silicon oxide are formed in a monocrystalline silicon wafer by oxidation through apertures in a layer of masking material a layer of polycrystalli ne silicon is provided between the masking and the wafer surface. As described an isolated transistor is formed in a 3 ohm cm. P-type silicon wafer by diffusing boron and arsenic respectively into one face at the desired locations of the isolation regions and an N+ subcollector, depositing a 4 Á epitaxial layer of N type 1À5 ohm cm silicon and a 0À1 Á layer of polycrystalline silicon from silane at 1050‹ and 700‹ C. respectively and then depositing a masking layer of silicon nitride 0À1-0À2 Á thick by reaction of silane and ammonia at 1050‹C. After etching grooves through the nitride into the silicon to a depth of Á the wafer is heated at 1000‹ C. in water saturated nitrogen to fill the grooves with oxide and out-diffuse the boron and arsenic to reach the oxide. After removing the nitride and optionally the polycrystalline silicon the surface is oxidized and the base zone 15 (Fig. 9) formed in island 123 by diffusion of boron while island 122 is masked with photoresist. The oxide exposed via photoresist mask 152, 153 is etched away and after removal of the mask phosphorus is diffused in to form an emitter zone within the base zone and a collector contact region 163 (Fig. 11) in island 122. Contact windows are then formed over the ease and emitter zones and region 163 exposed and aluminium vapour deposited overall and etched back to form the electrodes shown. |
