Physical unclonable function for non-volatile memory

A method of manufacturing an integrated circuit, comprising:

• forming a plurality of programmable memory cells on the integrated circuit;
• connecting the integrated circuit to a system configured to exchange signals with the integrated circuit;
• and
• using the system to generate a data set in a set of programmable memory cells in the plurality of programmable memory cells having a starting distribution of thresholds, by:
• scanning the set of programmable memory cells to identify a first subset of the set of programmable memory cells having thresholds in a first part of the starting distribution, and a second subset of the set of programmable memory cells having thresholds in a second part of the starting distribution;
• selecting the programmable memory cells using the addresses of the programmable memory cells in said at least one of the first and second subsets;
• applying a biasing operation to change threshold voltages of the selected programmable memory cells to establish a changed distribution of thresholds for the set of programmable memory cells, the changed distribution having a sensing margin between the first and second subsets;
• and
• reading the programmable memory cells in the set using a read voltage in said sensing margin.

An apparatus, comprising:

• a set of programmable memory cells on an integrated circuit;
• logic to generate a data set using the set of programmable memory cells, wherein the set of programmable memory cells has a starting distribution of thresholds, by:
• scanning the set of programmable memory cells to identify a first subset of the set of programmable memory cells having thresholds in a first part of the starting distribution, and a second subset of the set of programmable memory cells having thresholds in a second part of the starting distribution;
• selecting the programmable memory cells using the addresses of the programmable memory cells in said at least one of the first and second subsets;
• applying a biasing operation to change threshold voltages of the selected programmable memory cells to establish a changed distribution of thresholds for the set of programmable memory cells, the changed distribution having a sensing margin between the first and second subsets;
• and
• reading the programmable memory cells in the set using a read voltage in said sensing margin.

A product comprising:

• a computer readable non-transitory data storage medium storing computer instructions for a process to generate a data set on an integrated circuit including a set of programmable memory cells, executable by a system configured to connect to the integrated circuit, the process comprising:
• scanning the set of programmable memory cells to identify a first subset of the set of programmable memory cells having thresholds in a first part of a starting distribution, and a second subset of the set of the programmable memory cells having thresholds in a second part of the starting distribution;
• selecting the programmable memory cells using the addresses of the programmable memory cells in said at least one of the first and second subsets;
• applying a biasing operation to change threshold voltages of the selected programmable memory cells to establish a changed distribution of thresholds for the set of programmable memory cells, the changed distribution having a sensing margin between the first and second subsets;
• and
• reading the programmable memory cells in the set using a read voltage in said sensing margin.

A method for generating a data set on an integrated circuit including a set of programmable memory cells, comprising:

• in the set of programmable memory cells having thresholds in a starting distribution, scanning the set of programmable memory cells to identify a first subset of the set of the programmable memory cells having thresholds in a first part of the starting distribution, and a second subset of the set of the programmable memory cells having thresholds in a second part of the starting distribution;
• applying a biasing operation to change thresholds of memory cells in the starting distribution to establish a sensing margin between the first and second subsets;
• and
• providing the data set using the sensing margin.