Evidence of reduced self-heating in strained Si MOSFETs

Abstract

Pulsed measurements are used to investigate selfheating in strained-Si MOSFETs. From analysis of the data at elevated temperatures, the thermal resistances of the devices are extracted. These are found to be considerably lower than that obtained with a widely used theory. Thermal device simulations demonstrate that the discrepancy is due to an additional conduction path through the field oxide to overlapping aluminum contacts.

Improved Analog Performance in Strained-Si MOSFETs Using the Thickness of the Silicon–Germanium Strain-Relaxed Buffer as a Design Parameter

“…Since the mechanism of heat generation is similar for holes and electrons and the low thermal conductivity SiGe buffer is common to both devices, self heating also occurs in strained Si pMOSFETs on SiGe SRBs [24,25]. The pMOSFETs in the simulated inverter were not calibrated by measured data hence, the same self heating parameters defined for the nMOSFETs were used.…”

Heat Generation and Transport in SOI and GOI Devices

“…The simplest model illustrating the inverse proportionality of the device thermal resistance with its dimensions is R th = 1/(2kD) for the thermal spreading resistance of a heated disk (diameter D) on a semi-infinite plane with thermal conductivity k (21). This can be extended to the case of a The thermal resistances of single Cu vias and strained Si (on SiGe buffer) transistors (19,20) are included for comparison. The x-axis represents the FET gate lengths, and the via diameters.…”

“…Thermal resistance data reported in the literature over nearly two decades of research across many bulk silicon FET(5,14) and SOI device technologies(3)(4)(5)(15)(16)(17)(18). The thermal resistances of single Cu vias and strained Si (on SiGe buffer) transistors(19,20) are included for comparison. The x-axis represents the FET gate lengths, and the via diameters.…”

The impact of self-heating and SiGe strain-relaxed buffer thickness on the analog performance of strained Si nMOSFETs

“…Self-heating arises from the lower thermal conductivity of SiGe relative to Si, which means that the MOSFET is less capable of dissipating heat as the channel current is increased since the channel is separated from the substrate by a low thermal conductivity SRB layer [5,6]. The consequence is increased carrier scattering that lowers the drain current in saturation as the drain voltage is increased.…”