MULTIPLE DOPING LEVEL BIPOLAR JUNCTIONS TRANSISTORS AND METHOD FOR FORMING
First Claim
1. A process for forming bipolar junction transistors in a semiconductor substrate, the process comprising:
- forming a first doped tub region of a first dopant type within the substrate;
forming first, second, third and fourth doped sinker regions of a second dopant type within the substrate;
forming second and third tub regions of the second dopant type in the substrate;
concurrently forming first, second, third and fourth subcollector regions and a triple well region all of the second dopant type, wherein the triple well region and the second and the third tub regions cooperate to electrically isolate the first doped tub region from the substrate, and wherein each one of the first, second, third and fourth subcollector region cooperates with a respective one of the first, second, third and fourth doped sinker regions;
doping the second and the fourth subcollector regions with the second dopant type; and
doping a portion of the third and the fourth subcollector regions with the second dopant type.
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Abstract
A process for forming bipolar junction transistors having a plurality of different collector doping densities on a semiconductor substrate and an integrated circuit comprising bipolar junction transistors having a plurality of different collector doping densities. A first group of the transistors are formed during formation of a triple well for use in providing triple well isolation for complementary metal oxide semiconductor field effect transistors also formed on the semiconductor substrate. Additional bipolar junction transistors with different collector doping densities are formed during a second doping step after forming a gate stack for the field effect transistors. Implant doping through bipolar transistor emitter windows forms bipolar transistors having different doping densities than the previously formed bipolar transistors. According to one embodiment of the present invention, bipolar junction transistors having six different collector dopant densities (and thus six different breakdown characteristics) are formed.
23 Citations
11 Claims
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1. A process for forming bipolar junction transistors in a semiconductor substrate, the process comprising:
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forming a first doped tub region of a first dopant type within the substrate; forming first, second, third and fourth doped sinker regions of a second dopant type within the substrate; forming second and third tub regions of the second dopant type in the substrate; concurrently forming first, second, third and fourth subcollector regions and a triple well region all of the second dopant type, wherein the triple well region and the second and the third tub regions cooperate to electrically isolate the first doped tub region from the substrate, and wherein each one of the first, second, third and fourth subcollector region cooperates with a respective one of the first, second, third and fourth doped sinker regions; doping the second and the fourth subcollector regions with the second dopant type; and doping a portion of the third and the fourth subcollector regions with the second dopant type. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A process for forming bipolar junction transistors in a semiconductor substrate further comprising complimentary metal oxide semiconductor field effect transistors, the process comprising:
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forming a first doped tub of a first dopant type within the substrate; forming a second doped tub and a plurality of sinker regions of a second dopant type within the substrate; forming third and fourth doped tubs of the second doping type in the substrate; forming a triple well region and a first plurality of subcollector regions comprising a first doping level, wherein the triple well region and the first plurality of subcollector regions are of the second dopant type, and wherein the third and the fourth doped tubs cooperate with the triple well region to electrically isolate the first doped tub from the substrate, and wherein each one of the first plurality of subcollector regions cooperates with one of the plurality of sinker regions; forming structures associated with the complementary metal oxide semiconductor field effect transistors after forming the triple well region and the first plurality of subcollector regions, wherein one of the structures comprises a gate for each of the complementary metal oxide semiconductor field effect transistors; doping a first subset of the first plurality of subcollector regions to form a second plurality of subcollector regions comprising a second doping level; doping a second subset of the first plurality of subcollector regions to form a third plurality of subcollector regions comprising a third doping level; and doping a subset of the second plurality of subcollector regions to form a fourth plurality of subcollector regions comprising a fourth doping level. - View Dependent Claims (9)
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10. An integrated circuit device, comprising:
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a semiconductor substrate; and a BiCMOS block of transistors located on the substrate, comprising; a plurality of NMOS transistors formed on the semiconductor substrate; a plurality of PMOS transistors formed on the semiconductor substrate; and different classes of bipolar junction transistors formed on the semiconductor substrate, wherein each class of the bipolar junction transistors has a different breakdown voltage due to different collector doping densities.
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11. A method of fabricating an integrated circuit device, comprising:
forming a BiCMOS block of transistors on a semiconductor substrate, comprising; forming a plurality of NMOS transistors on the semiconductor substrate; forming a plurality of PMOS transistors on the semiconductor substrate; and forming different classes of bipolar junction transistors on the semiconductor substrate, wherein each class of the bipolar junction transistors has a different breakdown voltage due to different collector doping densities.
Specification