Study of Effect of Energy Filtering on Subthreshold Slope of Transistors
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Date
2020-06-05Author
Gothe, Pushkar Kiran
0000-0002-8471-3889
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The inability to scale down the supply voltage of transistors has been a limiting factor that leads to excessive power consumption. The supply voltage is forced to remain at a high
value (>0.5 V) due to the subthreshold slope limit of 60 mV/decade at room temperature for MOSFET devices. This high subthreshold slope value is caused by the thermal excitation of
electrons following the Fermi-Dirac distribution and is a limiting factor in the functionality of various modern electronic devices. This study investigated a new type of transistor in which the thermally excited electrons are filtered out by a quantum well state, suppressing the thermal excitation of electrons and thereby increasing the steepness of the subthreshold slope. Silicon-based transistors capable of filtering out thermally excited electrons have been fabricated. A 2 nm QW layer of Cr2O3 and 1-2 nm SiO2 tunnelling barrier were inserted between the source electrode and the Si channel, where thermally excited electrons in the source are filtered out by a discrete state of the Cr2O3 QW and tunnel to the Si channel. The I-V’s and subthreshold slopes of fabricated devices with and without the energy filter were compared. A steeper subthreshold slope was observed for the transistor with the energy filter. A steeper subthreshold slope was also observed for devices with decreasing gate length.