| 摘要 |
1353488 Semi-conductor devices PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 7 July 1971 [10 July 1970] 31840/71 Heading H1K An island 4 in the semi-conductor body of a monolithic integrated circuit is isolated from the rest of the body by a buried layer 5 beneath the island and a lateral isolation zone 9 surrounding it, the layer 5 and zone 9 both having the opposite conductivity type from the island 4 and the zone 9 separating the island 4 from a surrounding oxide layer 8 which is inset into the semi-conductor body. The island 4 comprises part of an N-type epitaxial layer 3 deposited on an N-type substrate 2, the P-type buried layer 5 being formed by diffusion into the substrate surface prior to deposition of the layer 3. The inset oxide layer 8 is prefreably formed by oxidation of the Si semi-conductor body within a recess selectively etched in the layer 3. The P-type isolation zone 9 is then formed by diffusion of Ga through a mask of silicon nitride, the Ga penetrating the oxide 8 to reach the Si of the epitaxial layer 3. In the structure shown one island 4 constitutes the base region of a transistor the collector region of which is defined by the buried layer 5 and the isolation zone 9 and the emitter region 7 of which is provided by diffusion into the island 4. Ion implantation is also referred to. Another island 4 contains a PN diode, and Schottky barrier diodes, MOS capacitors, PNPN structures and deposited metal resistors may also be incorporated into the circuit. Adjacent islands 4 may be interconnected by a common buried layer.
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