Eisuke Saneyoshi

A precise-tracking NBTI-degradation monitor independent of NBTI recovery effect

Scaling has accelerated transistor degradation with respect to aging, especially for Negative Bias Temperature Instability (NBTI), which can cause more than a 10% degradation in delay [1]. It is known that in NBTI conditions, delay degradation decreases quickly after the DC-stress has been removed. Conventional aging monitors [3][4] have difficulty in characterizing NBTI accurately because they require long-term observations (more than 1µs) of delay degradation, whilst recovery from delay degradation will be accomplished in less than 1µs [2].

A 1.1V 35μm × 35μm thermal sensor with supply voltage sensitivity of 2°C/10%-supply for thermal management on the SX-9 supercomputer

Presented here is a thermal sensor, based on transistor off-leakage current, that allows measurement error of less than 3.1degC at 90degC and less than 2degC at 10% Vdd deviation. For experimental evaluation, 11 thermal sensors, each of which occupied only 35 mum times 35 mum area, were placed on a chip, and both the location of a hotspot and the overall temperature distribution were successfully measured and agreed with simulation.