Method of operating integrated circuit embedded with non-volatile programmable memory having variable coupling related application data

• US 8,325,519 B2
• Filed: 01/21/2011
• Issued: 12/04/2012
• Est. Priority Date: 11/14/2007
• Status: Active Grant

• Current Assignee: Adeia Semiconductor Technologies LLC (f/k/a Invensas Corporation) (Adeia Inc.)
• Original Assignee: Adeia Semiconductor Technologies LLC (f/k/a Invensas Corporation) (Adeia Inc.)
• Inventors: Liu, David, Gross, John Nicholas
• Primary Examiner(s): Hoang, Huan
• Application Number:
  US13/011,606
• Publication Number:
  US 20110116314A1
• Time in Patent Office: 683 Days
• Field of Search: 365/185.23, 365/185.18, 365/185.03, 365/185, 365/8
• US Class Current: 365/185.03
• CPC Class Codes: G11C 16/0408 comprising cells containing floating gate transistors G11C16/0483, G11C16/0491 take precedence
• CPC Class Codes: G11C 16/0416 comprising cells containing a single floating gate transistor and no select transistor, e.g. UV EPROM
• CPC Class Codes: G11C 2216/10 Floating gate memory cells with a single polysilicon layer
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/42324 Gate electrodes for transistors with a floating gate
• CPC Class Codes: H01L 29/7883 charging by tunnelling of carriers, e.g. Fowler-Nordheim tunnelling
• CPC Class Codes: H10B 41/30 characterised by the memory core region
• CPC Class Codes: H10B 41/60 the control gate being a doped region, e.g. single-poly memory cell
• CPC Class Codes: H10B 69/00 Erasable-and-programmable ROM [EPROM] devices not provided for in groups H10B41/00 - H10B63/00, e.g. ultraviolet erasable-and-programmable ROM [UVEPROM] devices

Abstract

A programmable non-volatile device is operated with a floating gate that functions as a FET gate that overlaps a portion of a source/drain region and allows for variable coupling through geometry and/or biasing conditions. This allows a programming voltage for the device to be imparted to the floating gate through variable capacitive coupling, thus changing the state of the device. Multi-state embodiments are also possible. The invention can be used in environments such as data encryption, reference trimming, manufacturing ID, security ID, and many other applications.

Claims

1. A method of operating a one-time programmable (OTP) device situated on a substrate comprising:

in an OTP device including a floating gate, a source region and a drain region, wherein said floating gate is comprised of a material shared by at least one of an interconnect or another gate for a transistor device situated on the substrate and associated with at least one of a logic gate or a volatile memory, wherein the drain region overlaps a predetermined portion of said floating gate such that, at the predetermined portion, the drain region serves as a capacitive coupling to the floating gate, and wherein an amount of the capacitive coupling of the drain region to the floating gate is based on a predetermined number of N (N>

1) separate drain regions of the drain region overlapping said floating gate,

setting a threshold of said floating gate by selecting which of said N separate drain regions provide a current of channel hot electrons.

2. The method of claim 1, wherein N=2 and said threshold of said floating gate can be set to one of four (4) different values.

3. The method of claim 1, wherein N=2 and said threshold of said floating gate can be set to one of three (3) different values.

4. The method of claim 1, wherein N=3 and said threshold of said floating gate can be set to one of eight (8) different values.

5. The method of claim 1, wherein N=2 and said threshold of said floating gate can be set to one of more than 2 but less than 8 different values.

6. The method of claim 1, wherein said threshold is determined by a read voltage applied to one or more of said N separate drain regions.

7. The method of claim 6, wherein said read voltage is controlled to have a range of values which vary in time corresponding to threshold states of said floating gate.

8. A method of operating a one-time programmable (OTP) device situated on a substrate comprising:

in an OTP device including a floating gate, a source region and a drain region, wherein said floating gate is comprised of a material shared by at least one of an interconnect or another gate for a transistor device situated on the substrate and associated with at least one of a logic gate or a volatile memory, wherein the drain region overlaps a predetermined portion of said floating gate such that, at the predetermined portion, the drain region serves as a capacitive coupling to the floating gate, and wherein an amount of the capacitive coupling of the drain region to the floating gate is based on a variable programming voltage,

setting a threshold of said floating gate by selecting said variable programming voltage.