LVTSCR-like structure with internal emitter injection control
AssigneeNational Semiconductor Corporation
InventorsVladislav Vashchenko, Ann Concannon, Peter J. Hopper, Marcel ter Beek
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Abstract
In an ESD protection device using a LVTSCR-like structure, the holding voltage is increased by placing the p+ emitter outside the drain of the device, thereby retarding the injection of holes from the p+ emitter. The p+ emitter may be implemented in one or more emitter regions formed outside the drain. The drain is split between a n+ drain and a floating n+ region near the gate to avoid excessive avalanche injection and resultant local overheating.
Claims16
A LVTSCR-like ESD protection structure having a first p+ emitter, wherein the structure displays a two-stage snapback triggering characteristic created by providing an additional p-type emitter in an n-well of the structure.
A LVTSCR-like ESD protection structure, comprising
- a p-epitaxial layer or substrate,
- a n-well formed in the p-epitaxial layer or substrate,
- a first n+ region and a first p+ region formed in the p-epitaxial layer or substrate, or in a p-well in the p-epitaxial layer or substrate,
- a second n+ region and a second p+ region formed in the n-well, and
- at least one additional p+ region formed in the n-well defining a diode with the second n+ region with a feedback loop from the n-well or from a n-type region adjacent the additional p+ region, back to the second p+ region.
A method of increasing the holding voltage of a LVTSCR structure, comprising
- forming at least one additional p-type structure to define at least one diode additional p-n junction in a n-well of the LVTSCR, and
- providing a feedback loop from the cathode n-region of the diode p-n junction located furthest from the p+ emitter of the LVTSCR, back to the p+ emitter.
A method of increasing the holding voltage of a LVTSCR structure, comprising
- forming one or more diode structures in a n-well of the LVTSCR structure and
- forming a feedback loop from the cathode of the diode located furthest from the p+ emitter of the LVTSCR back to the p+ emitter of the LVTSCR.
Dependencies are inferred from the claim text.