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