ESD protection for semiconductor products
First Claim
1. A semiconductor product including a device configured along a planar surface of a semiconductor substrate of a first conductivity type to provide electrostatic discharge protection, said device comprising:
- first and second spaced-apart diffusions of a second conductivity type each formed along the substrate surface and extending into the substrate to form a pn junction, one of said junctions having a lateral portion extending about a plane parallel to the substrate surface and a second portion extending from the lateral portion toward the substrate surface, a sufficiently large region in the lateral portion having dopants of the first and second polarities for proving a substantially lower breakdown voltage than the second portion such that during conduction across the junction the maximum current density through the lateral portion is greater than the maximum current density through the second portion.
7 Assignments
0 Petitions
Accused Products
Abstract
Device 60 in FIG. 3 has junctions 86 each with a lateral portion 90 and a second portion 92 extending upward toward the surface 12 from the lateral portion 90. The lateral portions 90, as illustrated in FIG. 3, are more or less formed along a plane parallel with the surface 12. The upwardly extending portions 92 include characteristic curved edges of the diffusion fronts which are associated with the planar process. With the regions 80 and 82 each having relatively high net dopant concentrations of different conductivity types, each lateral junction portion 90 includes a relatively large sub region 96 which extends more deeply into the layer 10. When compared to other portions of the junctions 86, the subregions 96 are characterized by a relatively low breakdown voltage so that ESD current is initially directed vertically rather than laterally.
54 Citations
20 Claims
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1. A semiconductor product including a device configured along a planar surface of a semiconductor substrate of a first conductivity type to provide electrostatic discharge protection, said device comprising:
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first and second spaced-apart diffusions of a second conductivity type each formed along the substrate surface and extending into the substrate to form a pn junction, one of said junctions having a lateral portion extending about a plane parallel to the substrate surface and a second portion extending from the lateral portion toward the substrate surface, a sufficiently large region in the lateral portion having dopants of the first and second polarities for proving a substantially lower breakdown voltage than the second portion such that during conduction across the junction the maximum current density through the lateral portion is greater than the maximum current density through the second portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An ESD protection device configured along a planar surface of a semiconductor substrate of a first conductivity type to provide electrostatic discharge protection, said device comprising:
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first and second spaced-apart diffusions of a second conductivity type formed along the substrate surface and extending into the substrate to form a pn junction, one of said junctions having a lateral portion extending in directions parallel to the substrate surface and a second portion extending from the lateral portion toward the substrate surface, the lateral portion including a sub region having a breakdown voltage which is substantially lower than the minimum breakdown voltage across the second portion of the junction, said region having a minimum lateral width of 0.55 microns and of sufficient area relative to the area of the entire pn junction to carry the majority of current when the pn junction conducts current during an ESD event. - View Dependent Claims (13, 14, 15)
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16. A semiconductor product having an ESD protection device formed thereon, comprising:
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a lightly doped semiconductor substrate of a first conductivity type having an upper surface formed along a plane;
a structure formed along the upper surface;
first and second source/drain regions of a second conductivity type, each formed in the surface and positioned on a different side of the structure, each forming a pn junction with the substrate, each pn junction including a lateral portion extending in directions parallel with the upper surface and a second portion extending from the lateral portion toward the surface;
an implanted region of the first conductivity type positioned to provide a relatively high dopant concentration along a lateral portion, wherein, during an ESD event, said protection device is characterized by a net low resistance and high current flow through the lateral portion of the junction relative to the second portion of the junction. - View Dependent Claims (17, 18, 19, 20)
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Specification