ESD protection structure
View Patent ↗An ESD protection structure formed within a semiconductor substrate of an integrated circuit device. The ESD protection structure comprises a thyristor structure being formed from a first P-doped section forming an anode of the thyristor structure, a first N-doped section forming a collector node of the thyristor structure, a second P-doped section, and a second N-doped section forming a cathode of the thyristor structure. A low-resistance coupling is provided between an upper surface region of the collector node of the thyristor structure and the anode of the thyristor structure.
1. An electrostatic discharge, ESD, protection structure formed within a semiconductor substrate of an integrated circuit device, the ESD protection structure comprising:
a first thyristor structure being formed from
a first P-doped section forming an anode of the first thyristor structure,
a second P-doped section,
a first N-doped section forming a collector node of the first thyristor structure, wherein the first N-doped section is located between the first and second P-doped sections,
a second N-doped section forming a cathode of the first thyristor structure, wherein the second N-doped section is located in the second P-doped section; and
a first low-resistance coupling between an upper surface region of the collector node of the first thyristor structure and the anode of the first thyristor structure.
2. The ESD protection structure of claim 1 , wherein the first low-resistance coupling comprises a metalized layer formed over an N-doped contact region within the upper surface region of the collector node of the first thyristor structure, and the metalized layer is coupled to the anode of the first thyristor structure.
3. The ESD protection structure of claim 1 , wherein the first N-doped section of the first thyristor structure comprises a deep N-well structure and an N-doped buried layer.
4. The ESD protection structure of claim 1 , wherein the first P-doped section forming the anode of the first thyristor structure is coupled to a contact of the integrated circuit device to be protected.
5. The ESD protection structure of claim 1 , wherein the second N-doped section forming the cathode of the first thyristor structure is coupled to a negative supply node to which ESD currents are to be shunted.
6. The ESD protection structure of claim 1 , wherein:
the first P-doped section forming the anode of the first thyristor structure comprises a first P-doped well formed within a first P-doped region of an epitaxial layer, and a P-doped contact region within an upper surface of the first P-doped well;
the second P-doped section comprises a second P-doped well formed within a second P-doped region of the epitaxial layer;
the first N-doped section forming the collector node of the first thyristor structure comprises a part of a deep N-well structure between the first and second P-doped regions of the epitaxial layer; and
the second N-doped section forming the cathode of the first thyristor structure comprises an N-doped contact region within an upper surface of the second P-doped well.
7. The ESD protection structure of claim 1 , wherein:
the first P-doped section forming the anode of the first thyristor structure comprises a first P-doped contact region within an upper surface of enlarged deep N-well (DPN) region;
the first N-doped section forming a collector node of the first thyristor structure comprises the enlarged DPN region;
the second P-doped section comprises a second P-doped well formed within a P-doped region of an epitaxial layer; and
the second N-doped section forming the cathode of the first thyristor structure comprises an N-doped contact region within an upper surface of the second P-doped well.
8. The ESD protection structure of claim 1 comprising the first thyristor structure and a second thyristor structure; wherein:
a second low-resistance coupling is provided between an upper surface region of a collector node of the second thyristor structure and an anode of the second thyristor structure.
9. The ESD protection structure of claim 8 , wherein:
the first P-doped section forming the anode of the first thyristor structure is coupled to a contact of the integrated circuit device to be protected;
an N-doped section forming a cathode of the second thyristor structure is coupled to a negative supply node to which ESD currents are to be shunted; and
the second N-doped section forming the cathode of the first thyristor structure and a P-doped section forming an anode of the second thyristor structure are coupled to a common node.
10. An integrated circuit device comprising at least one semiconductor substrate comprising at least one electrostatic discharge, ESD, protection structure according to claim 1 .
11. A method of fabricating an electrostatic discharge, ESD, protection structure within a semiconductor substrate of an integrated circuit device; the method comprising:
forming a thyristor structure within the semiconductor substrate, the thyristor structure being formed from:
a first P-doped section forming an anode of the thyristor structure,
a second P-doped section,
a first N-doped section forming a collector node of the thyristor structure, wherein the first N-doped section is formed between the first and second P-doped sections,
a second N-doped section forming a cathode of the thyristor structure, wherein the second N-doped section is formed in the second P-doped section; and
providing a low-resistance coupling between an upper surface region of the collector node of the thyristor structure and the anode of the thyristor structure.