Reliable MOSFET operation using two-phase microfluidics in the presence of high heat flux transients

Abstract

Randomly generated heat flux transients affect the reliability of advanced integrated circuits and can induce severe nonlinearity in the device response, resulting in the degradation of a gate dielectric in metal oxide field effect transistors (MOSFETs). The effect of high heat flux transients on MOSFET operation and mitigation, using single-phase and two-phase on-chip microfluidics, is reported in this paper. A prototype comprising monolithically integrated MOSFETs, resistance temperature detector (RTD) arrays, simulated transient source (microheaters) and microfluidic networks was developed. The application of a 10 s transient (153 W cm −2 ) led to the degradation of subthreshold swing (S) from 120 to 240 mV/decade. However, in the presence of water flow, effective mitigation of S (up to 75%) is observed. The rate of mitigation is higher at lower flow rates because of the higher heat-transfer efficiency for two-phase flow. Thus, an appropriate selection of flow parameters can lead to optimized cooling. Additionally, we propose a strategy to localize the transient heat sources based on the temperature profiles generated using an on-chip, distributed RTD sensor array. The proposed methodology can be applied in practical integrated circuits for localization and characterization of heat sources leading to modifications in the circuit design or process integration steps.

Pressure Drop Measurements With Boiling in Diverging Microchannel

“…Microelectronics devices, which include a variety of applications such as personal computers, servers, laser diodes, and RF devices are pushing the heat flux density requirements to higher levels. Singh et al (2009aSingh et al ( , 2011 for the first time performed in situ impact analysis of very high heat flux transients on the characteristics of RTD, p-n diode and MOSFET. The authors showed that the p-n diode power exponent factor is highly sensitive to transient heat flux conditions.…”

“…The authors showed that the p-n diode power exponent factor is highly sensitive to transient heat flux conditions. Singh et al (2011) reported that the rate of mitigation in MOSFET operation is higher at lower flow rates because of the higher heat transfer efficiency of two phase flow. They also proposed a technique for localizing hotspots by utilizing an on-chip distributed RTD sensor array.…”