Semiconductor structure having two levels of buried regions
First Claim
1. A semiconductor structure comprising (a) a monocrystalline semiconductive substrate, (b) a lower monocrystalline semiconductive layer that overlies the substrate and adjoins it along a lower semiconductor interface, and (c) an upper monocrystalline semiconductive layer that overlies the lower semiconductive layer and adjoins it along an upper semiconductor interface, wherein:
- first and second lower buried regions of opposite conductivity types are situated along the lower semiconductor interface;
first and second upper buried regions of opposite conductivity types are situated along the upper semiconductor interface;
the upper semiconductive layer contains a plurality of P-type device regions and a plurality of N-type device regions; and
one of the device regions of each conductivity type laterally meets one of the device regions of the other conductivity type and vertically extends into the upper semiconductive layer to a depth sufficient to meet one of the upper buried regions.
1 Assignment
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Accused Products
Abstract
Integrated circuits suitable for high-performance applications, especially mixed signal products that have analog and digital sections, are fabricatable from a semiconductor structure having two levels of buried regions. In a typical embodiment lower buried regions of opposite conductivity types are situated along a lower semiconductor interface between a semiconductive substrate and an overlying lower semiconductive layer. Upper buried regions of opposite conductivity type are similarly situated along an upper semiconductor interface between the lower semiconductive layer and an overlying upper semiconductive layer. The upper semiconductive layer contains P-type and N-type device regions in which transistor zones are situated. The semiconductor structure is normally configured so that at least one of each of the P-type and N-type device regions is electrically isolated from the substrate. Complementary bipolar transistors can be integrated with complementary field-effect transistors in the structure.
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Citations
114 Claims
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1. A semiconductor structure comprising (a) a monocrystalline semiconductive substrate, (b) a lower monocrystalline semiconductive layer that overlies the substrate and adjoins it along a lower semiconductor interface, and (c) an upper monocrystalline semiconductive layer that overlies the lower semiconductive layer and adjoins it along an upper semiconductor interface, wherein:
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first and second lower buried regions of opposite conductivity types are situated along the lower semiconductor interface; first and second upper buried regions of opposite conductivity types are situated along the upper semiconductor interface; the upper semiconductive layer contains a plurality of P-type device regions and a plurality of N-type device regions; and one of the device regions of each conductivity type laterally meets one of the device regions of the other conductivity type and vertically extends into the upper semiconductive layer to a depth sufficient to meet one of the upper buried regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 76, 77, 78, 79, 80, 97, 107, 108)
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22. A semiconductor structure comprising (a) a monocrystalline semiconductive substrate, (b) a lower monocrystalline semiconductive layer that overlies the substrate and adjoins it along a lower semiconductor interface, and (c) an upper monocrystalline semiconductive layer that overlies the lower semiconductive layer and adjoins it along an upper semiconductor interface, wherein:
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the substrate comprises a major substrate region of a first conductivity type; a lower buried region of the first conductivity type more heavily doped than the major substrate region is situated along the lower semiconductor interface and meets the major substrate region; a lower buried region of a second conductivity type opposite to the first conductivity type is situated along the lower semiconductor interface and meets the major substrate region; an upper buried region of the first conductivity type is situated along the upper semiconductor interface; an upper buried region of the second conductivity type is situated along the upper semiconductor interface; the upper semiconductive layer contains a device region of the first conductivity type and a device region of the second conductivity type laterally meeting the device region of the first conductivity type; and each device region vertically extends into the upper semiconductive layer to a depth sufficient to meet one of the upper buried regions. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 81, 98, 99, 109, 110)
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60. A semiconductor structure comprising (a) a semiconductive substrate, (b) a lower semiconductive layer that overlies the substrate and adjoins it along a lower semiconductor interface, and (c) an upper semiconductive layer that overlies the lower semiconductive layer and adjoins it along an upper semiconductor interface, wherein:
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the substrate comprises a major substrate region of a first conductivity type; a lower buried region of a second conductivity type opposite to the first conductivity type is situated along the lower semiconductor interface and meets the major substrate region; an upper buried region of the first conductivity type is situated along the upper semiconductor interface and at least partially overlies the lower buried region of the second conductivity type; an upper buried region of the second conductivity type is situated along the upper semiconductor interface; a device region of the first conductivity type more lightly doped than the upper buried region of the first conductivity type vertically extends through the upper semiconductive layer to meet the upper buried region of the first conductivity type; and a device region of the second conductivity type vertically extends largely through the upper semiconductive layer and laterally meets the device region of the first conductivity type. - View Dependent Claims (61, 62, 63, 64, 65, 66, 67, 91, 92, 100, 101, 102, 111, 112)
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68. An integrated semiconductor structure comprising:
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a major region of a first conductivity type; a vertical isolation region of a second conductivity type opposite to the first conductivity type overlying the major region; a buffer region of the first conductivity type overlying the vertical isolation region; and a first bipolar transistor that comprises; a main collector zone of the first conductivity type overlying and meeting the buffer region such that the main collector zone has a higher net peak dopant concentration than the buffer region and such that, where the main collector zone generally meets the buffer region, the net dopant concentration of the buffer region has a different vertical gradient than the net dopant concentration of the main collector zone; a base zone of the second conductivity type overlying at least part of the main collector zone; and an emitter zone of the first conductivity type overlying at least part of the base zone. - View Dependent Claims (69, 70, 71, 72, 73, 74, 75)
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82. A semiconductor structure comprising (a) a monocrystalline semiconductive substrate, (b) a lower monocrystalline semiconductive layer that overlies the substrate and adjoins it along a lower semiconductor interface, and (c) an upper monocrystalline semiconductive layer that overlies the lower semiconductive layer and adjoins it along an upper semiconductor interface, wherein:
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at least one first lower buried region of a first conductivity type is situated along the lower semiconductor interface; at least one second lower buried region of a second conductivity type opposite to the first conductivity type is situated along the lower semiconductor interface, each second lower buried region being laterally separated from each first lower buried region along the lower semiconductor interface; at least one first upper buried region of the first conductivity type is situated along the upper semiconductor interface; at least one second upper buried region of the second conductivity type is situated along the upper semiconductor interface; the upper semiconductive layer contains a plurality of P-type device regions and a plurality of N-type device regions; and one of the device regions of each conductivity type laterally meets one of the device regions of the other conductivity type and vertically extends into the semiconductive layer to a depth sufficient to meet one of the upper buried regions. - View Dependent Claims (83, 84, 85, 86, 87, 88, 89, 90, 103, 104, 105, 106, 113, 114)
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93. A semiconductor structure comprising (a) a semiconductive substrate, (b) a lower semiconductive layer that overlies the substrate and adjoins it along a lower semiconductor interface, and (c) an upper semiconductive layer that overlies the lower semiconductive layer and adjoins it along an upper semiconductor interface, wherein:
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the substrate comprises a major substrate region of a first conductivity type; a lower buried region of a second conductivity type opposite to the first conductivity type is situated along the lower semiconductor interface and meets the major substrate region; an upper buried region of the first conductivity type is situated along the upper semiconductor interface and at least partially overlies the lower buried region of the second conductivity type; a device region of the first conductivity type more lightly doped than the upper buried region of the first conductivity type vertically extends through the upper semiconductive layer to meet the upper buried region of the first conductivity type; a first device region of the second conductivity type vertically extends largely through the upper semiconductive layer; and a second device region of the second conductivity type vertically extends largely through the upper semiconductive layer, is spaced laterally apart from the first device region of the second conductivity type, and at least partially overlies the upper buried region of the first conductivity type, the device and upper buried regions of the first conductivity type, including any directly underlying semiconductive material of the first conductivity type, being surrounded along their joint outside surface within the semiconductive layers and the substrate by a tub of the second conductivity type, the tub comprising the first device and lower buried regions of the second conductivity type. - View Dependent Claims (94, 95, 96)
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Specification