A Method to Improve Reliability in a 65-nm SRAM PUF Array

Abstract

A modified weak SRAM physical unclonable function (PUF) is proposed which is much more reliable than prior-art SRAM PUFs. The proposed PUF was fabricated in TSMC 65-nm process. A novel preselection test was run on these PUF arrays and is shown to eliminate all of the unstable cells (20%–25%). This PUF can drastically reduce the need for error correction codes. In addition, the preselection test can be accomplished in one VDD/temperature corner, which reduces the testing cost of finding unstable bits across many such corners, as is done in the prior art.