Synopsys, Inc.

Oleg Ivanov

Andrew Edward Horch

Larry Lingjer Wang

Grigori Grigoriev

Roman Gavrilov

A semiconductor memory includes, in part, M×N select transistors disposed along M rows and N columns, where M and N are integers greater than or equal to 2. The memory further includes, in part, a first set of M wells each configured to be biased independently of the remaining M−1 wells. Each well has formed therein N of the select transistors each having a source/drain terminal coupled to the same bitline corresponding to a different one of M bitlines of the memory. The memory further includes, in part, M×N anti-fuses. Each anti-fuse is associated and forms a bitcell with a corresponding one of the M×N select transistors.

One time programmable bitcell with select device in isolated well

A method and system are used to generate random values for Physical Unclonable Function (PUF) for use in cryptographic applications. A PUF value generation apparatus comprises two dielectric breakdown based anti-fuses and at least one current limiting circuit connected between anti-fuses and power rails. Two anti-fuses are connected in parallel for value generation in programming by applying high voltage to both anti-fuses at the same time. Time for dielectric breakdown under high voltage stress is of random nature and therefore unique for each anti-fuse cell. Therefore the random time to breakdown causes one cell to break before another, causing high breakdown current through the broken cell. Once high breakdown current through one broken or programmed cell is established, a voltage drop across a current limiting circuit leads to decreased voltage across both cells, thereby slowing the time dependent breakdown process in the second cell and preventing it from breakage under programming conditions.

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Ottawa, Canada

Oleg Ivanov