Enhanced FDSOI physically unclonable function

1. An integrated circuit, comprising:

a plurality of transistor devices each having a back gate that includes a region formed distinct from a body of each of the plurality of transistor devices; and

a controller connected to the back gate to apply voltages to the back gate, wherein the controller includes a first mode that includes a first voltage for operational threshold voltages for the plurality of transistor devices and a second mode that includes a second voltage that enhances threshold voltage variability of the plurality of transistor devices to provide a physically unclonable function (PUF) for chip identification.

2. The circuit as recited in claim 1 , wherein the plurality of transistor devices includes field effect transistors having the back gate formed in a well of a semiconductor substrate.

3. The circuit as recited in claim 2 , wherein the semiconductor substrate includes a fully depleted semiconductor-on-insulator substrate.

4. The circuit as recited in claim 1 , wherein the circuit includes at least one ring oscillator.

5. The circuit as recited in claim 1 , wherein the plurality of transistor devices includes n-type field effect transistors (NFETs) and the second voltage includes a positive back gate bias.

6. The circuit as recited in claim 1 , wherein the plurality of transistor devices includes p-type field effect transistors (PFETs) and the second voltage includes a negative back gate bias.

7. The circuit as recited in claim 1 , wherein the PUF for chip authentication includes a threshold voltage variability pattern of the plurality of transistor devices.

8. The circuit as recited in claim 7 , wherein the PUF is employed by a computer system to authenticate an identity of the integrated circuit.

9. The circuit as recited in claim 1 , wherein the back gate is electrically isolated from a body of each of the plurality of transistor devices.

10. An integrated circuit, comprising:

a fully depleted semiconductor-on-insulator substrate (FDSOI) having a back gate of field effect transistors that includes a region formed distinct from a body of each of the field effect transistors formed below a buried dielectric layer of the FDSOI substrate, the FDSOI substrate including a semiconductor layer forming source regions, channel regions and drain regions;

a front gate structure formed on the semiconductor layer to form the field effect transistors; and

a controller connected to the back gate to apply voltages to the back gate of the field effect transistors, wherein the controller includes a first mode that includes a first voltage for operational threshold voltages for the field effect transistors and a second mode that includes a second voltage that enhances threshold voltage variability of the field effect transistors to provide a physically unclonable function (PUF) for chip identification.

11. The circuit as recited in claim 10 , wherein the field effect transistors include the back gate formed in a well of a base semiconductor substrate.

12. The circuit as recited in claim 10 , wherein the circuit includes at least one ring oscillator.

13. The circuit as recited in claim 12 , wherein the circuit includes:

at least two multiplexers configured to receive input from the at least one ring oscillator and to receive a challenge; and

a response component to determine a response to the challenge for authentication of a chip including the circuit.

14. The circuit as recited in claim 10 , wherein the field effect transistors include n-type field effect transistors (NFETs) and the second voltage includes a positive back gate bias.

15. The circuit as recited in claim 10 , wherein the field effect transistors include p-type field effect transistors (PFETs) and the second voltage includes a negative back gate bias.

16. The circuit as recited in claim 10 , wherein the PUF for chip authentication includes a threshold voltage variability pattern of the field effect transistors.

17. The circuit as recited in claim 16 , wherein the PUF is employed by a computer system to authenticate an identity of the integrated circuit.