Verification of Threshold Voltage Variation of Scaled Transistors with Ultralarge-Scale Device Matrix Array Test Element Group

Randomness of threshold voltage ( V T ) variations of negative channel field effect transistors (NFETs) and positive channel field effect transistors (PFETs) in the 65 nm technology is precisely examined. For this purpose, an ultralarge-scale device matrix array test element group (DMA-TEG) that contains 1 million single-size metal–oxide–semiconductor field-effect transistors (MOSFETs) has been designed and fabricated, and a very rapid measurement system has been developed. By evaluating V T of a very large number of MOSFETs, V T variation can be precisely evaluated. This rapid measurement is achieved by parallel address signal input, optimization of the measurement program, and 4-chip parallel measurements. The measured V T variations are decomposed into random and systematic components. The results reveal that the random component is overwhelmingly dominant in the V T variations in the 65 nm technology and that the V T variations exhibit a normal distribution up to ±5σ.