Electrostatic discharge protection circuit
First Claim
1. An electrostatic discharge protection circuit which during operation is connected to first and second power nodes, said protection circuit formed in a semiconductor substrate, comprising:
- a single p-type well inside said semiconductor substrate;
a first diffusion region of n-type located in said p-type well to provide a signal input end;
a second diffusion region of p-type located in said p-type well and connected to the first power node;
an n-type well contacting said p-type well in said semiconductor substrate;
a third diffusion region of n-type connected to the second power node and located in said n-type well; and
a fourth diffusion region being more lightly doped than said n-type well and located within said n-type well and located between said p-type well and said third diffusion region.
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Accused Products
Abstract
An electrostatic discharge protection circuit formed in a semiconductor substrate includes a vertical bipolar junction transistor having a base which is grounded, an emitter connected to an output/input bonding pad of an integrated circuit, and a collector connected to a high power source via a resistor. The resistor is a parasitic resistor created by controlling the distance between the diffusion regions or the distance between a p-type well region and an n-type well region or formed by a lightly doped diffusion region in the semiconductor substrate to prevent current crowding and increase electrostatic protection.
28 Citations
11 Claims
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1. An electrostatic discharge protection circuit which during operation is connected to first and second power nodes, said protection circuit formed in a semiconductor substrate, comprising:
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a single p-type well inside said semiconductor substrate; a first diffusion region of n-type located in said p-type well to provide a signal input end; a second diffusion region of p-type located in said p-type well and connected to the first power node; an n-type well contacting said p-type well in said semiconductor substrate; a third diffusion region of n-type connected to the second power node and located in said n-type well; and a fourth diffusion region being more lightly doped than said n-type well and located within said n-type well and located between said p-type well and said third diffusion region. - View Dependent Claims (2, 3)
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4. An electrostatic discharge protection circuit which during operation is connected to first and second power nodes, said protection circuit formed in a semiconductor substrate of a first conductivity type, said protection circuit comprising:
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a single well of a second conductivity type formed inside said semiconductor substrate; a first diffusion region of the first conductivity type located in said well that provides a signal input end; a second diffusion region of the second conductivity type located in said well and connected to the first power node; and a third diffusion region of the first conductivity type connected to the second power node and located in said semiconductor substrate, said third diffusion region spaced from said well by a distance of about 3 to 10 microns. - View Dependent Claims (6, 7, 10, 11)
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5. An electrostatic discharge protection circuit which during operation is connected to first and second power nodes, said protection circuit formed in a semiconductor substrate of n-type, comprising:
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a single p-type well inside said semiconductor substrate; a first diffusion region of p-type located in said p-type well to provide a signal input end; a second diffusion region of n-type located in said p-type well and connected to the first power node; an n-type well near said p-type well in said semiconductor substrate; and a third diffusion region connected to the second power node, located in said n-type well and maintained at a distance of about 3-10 microns from said p-type well. - View Dependent Claims (8, 9)
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Specification