Zero cost NVM cell using high voltage devices in analog process
First Claim
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1. A programmable non-volatile device situated on a substrate comprising:
- a floating gate configured to store non-volatile memory data for the device;
wherein said floating gate is comprised of a material that is also used as a gate for a separate high voltage transistor driver device also situated on the substrate;
a source region coupled to a first terminal; and
a drain region coupled to a second terminal; and
a drift region coupled to the drain region;
wherein the drift region overlaps a sufficient portion of said gate such that a programming voltage for the device applied to said first terminal of said drain region and second terminal of said source region can be imparted to said floating gate through areal capacitive coupling;
further wherein at least some structures of the device, including said floating gate, source region, drain region and drift region are constructed during analog process manufacturing steps also used to make high voltage devices of an integrated circuit incorporating the programmable non-volatile device.
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Abstract
A non-volatile memory cell and array structure is disclosed situated within a high voltage region of an integrated circuit. The cell utilizes capacitive coupling based on an overlap between a gate and a drift region to impart a programming voltage. Programming is effectuated using a drain extension which can act to inject hot electrons. The cell can be operated as a one-time programmable (OTP) or multiple-time programmable (MTP) device. The fabrication of the cell relies on processing steps associated with high voltage devices, thus avoiding the need for additional masks, manufacturing steps, etc.
28 Citations
23 Claims
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1. A programmable non-volatile device situated on a substrate comprising:
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a floating gate configured to store non-volatile memory data for the device; wherein said floating gate is comprised of a material that is also used as a gate for a separate high voltage transistor driver device also situated on the substrate; a source region coupled to a first terminal; and a drain region coupled to a second terminal; and a drift region coupled to the drain region; wherein the drift region overlaps a sufficient portion of said gate such that a programming voltage for the device applied to said first terminal of said drain region and second terminal of said source region can be imparted to said floating gate through areal capacitive coupling; further wherein at least some structures of the device, including said floating gate, source region, drain region and drift region are constructed during analog process manufacturing steps also used to make high voltage devices of an integrated circuit incorporating the programmable non-volatile device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 16, 17)
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11. A lateral diffused metal oxide semiconductor (LDMOS) structure comprising:
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a floating gate adapted to store charge carriers representing a data value; a source region coupled to a first terminal; and a drain region coupled to a second terminal; and a drift region coupled to the drain region, said drift region having a first portion which is overlapping at least a first areal portion of said floating gate and a second notched portion; the LDMOS being situated in a high voltage driver region and adapted such that a voltage applied to said first terminal of said drain region and second terminal of said source region can be imparted to said floating gate through areal capacitive coupling; wherein the LDMOS structure can function as a memory cell. - View Dependent Claims (12, 13, 18, 19, 20)
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14. A lateral drift N-type metal oxide semiconductor (LDMOS) structure comprising:
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a floating gate having no contacts to a voltage supply; a source region coupled to a first terminal; and a drain region coupled to a second terminal; and a drift region coupled to the drain region, said drift region having a first portion which is overlapping at least a first areal portion of said floating gate and a second notched portion; the LDMOS structure being situated in a high voltage driver region and adapted such that a voltage applied to said first terminal of said drain region and second terminal of said source region can be imparted to said floating gate through areal capacitive coupling; wherein the LDMOS structure can function as a memory cell. - View Dependent Claims (21, 22)
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15. A programmable non-volatile device situated in a high voltage circuit portion of a substrate comprising:
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a floating gate configured to store non-volatile memory data for the device; wherein said floating gate is comprised of a material that is also used as a gate for a high voltage transistor driver device also situated in the high voltage circuit portion of the substrate; a source region coupled to a first terminal; and a drain region coupled to a second terminal, said drain region having an extension which abuts at least a first edge of said floating gate; and a drift region coupled to the drain region which overlaps a sufficient portion of said gate such that a programming voltage for the device applied to said first terminal of said drain region and second terminal of said source region can be imparted to said floating gate through areal capacitive coupling; wherein said drain extension extends within a notched portion of said drift region; further wherein said drain region can inject hot electrons along said first edge of said floating gate in response to said programming voltage; and further wherein the programmable non-volatile device is manufactured at least in part during a high voltage analog process. - View Dependent Claims (23)
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Specification