Systems and methods for threshold voltage modification and detection
A memory device includes a memory array of a set of memory cells. Each memory cell of the set of memory cells includes at least one transistor and at least one capacitor. The memory array includes at least one programmed memory cell. The programmed memory cell is selectively programmed by applying hot-carrier injection (HCI) to a transistor of the programmed memory cell. The programmed memory cell may provide an indication of pattern data that may be used to facilitate functionality such as data encryption, data decryption, implementation of a particular memory device operation mode, and/or machine-implemented instructions.
1. One-time programming (OTP) injection circuitry, comprising circuitry configured to:
program at least one memory cell of a memory array by applying hot-carrier injection (HCI) to a transistor of the at least one memory cell; and
perform an HCI application cycle, comprising:
initializing the at least one memory cell for programming;
then raising a plate voltage of the at least one memory cell;
then lowering a selected digit of the memory cell to introduce a strong HCI; and
then lowering the plate voltage of the at least one memory cell.
2. The OTP injection circuitry of claim 1 , comprising circuitry configured to:
determine a desired pattern to introduce into the memory array;
identify memory cells of the memory array to be programmed to form the desired pattern; and
applying the HCI to each of the identified memory cells of the memory area to be programmed.
3. The OTP injection circuitry of claim 1 , comprising circuitry configured to:
repetitively perform the HCI application cycle until a target threshold voltage (Vth) change is reached.
4. The OTP injection circuitry of claim 3 , wherein the target threshold voltage (Vth) change comprises a range of 200-300 mV.
5. A method, comprising:
identifying one or more programmed memory cells of a memory array, wherein the one or more programmed memory cells are programmed by applying hot-carrier injection (HCI) to a transistor of the one or more programmed memory cells;
based upon the one or more programmed memory cells, identifying programmed pattern data; and
implementing one or more data processing functions based upon the programmed pattern data;
wherein identifying the one or more programmed memory cells, comprises:
initializing the one or more programmed memory cells, by writing a “1” to the one or more programmed memory cells and a reference memory cell, a reference digit, or both, when a word line voltage of the one or more programmed memory cells is sufficient to change a capacitor voltage of the one or more programmed memory cells and a capacitor voltage of the reference memory cell, the reference digit, or both;
then modifying the word line voltage to a voltage sufficient to change a capacitor voltage of the reference memory cell, the reference digit, or both, but not the capacitor voltage of the one or more programmed memory cells, when a “0” is written to the one or more programmed memory cells and the reference memory cell, the reference digit or both;
then writing the “0” to the one or more programmed memory cells and the reference memory cell, the reference digit, or both;
then comparing the capacitor voltage of the one or more programmed memory cells with the capacitor voltage of the reference memory cell, the reference digit, or both; and
when the capacitor voltage of the programmed memory cell differs from the capacitor voltage of the reference memory cell, the reference digit, or both, determining that the one or more programmed memory cells are programmed.
6. The method of claim 5 , comprising:
based upon the programmed pattern data: implementing decryption, implementing encryption, implementing a boot-up routine, implementing a particular memory device operating mode, or any combination thereof.