In this paper, we propose a novel operation of a MOSFET that is suitable for ultra-low voltage (0.6 V and below) VLSI circuits. Experimental demonstration was carried out in a Silicon-On-Insulator (SOI) technology. In this device, the threshold voltage of the device is a function of its gate voltage, i.e., as the gate voltage increases the threshold voltage (Vt) drops resulting in a much higher current drive than standard MOSFET for low-power supply voltages. On the other hand, Vt is high at Vgs = 0, therefore the leakage current is low. We provide extensive experimental results and two-dimensional (2-D) device and mixed-mode simulations to analyze this device and compare its performance with a standard MOSFET. These results verify excellent inverter dc characteristics down to V dd = 0:2 V, and good ring oscillator performance down to 0.3 V for Dynamic Threshold-Voltage MOSFET (DTMOS). engineering from the Massachusetts Institute of Technology, Cambridge, in 1975, and the M.S.

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Abstruct-A new mode of operation for Silicon-On-Insulator (SOI) MOSFET is experimentally investigated. This mode gives rise to a Dynamic Threshold voltage MOSFET (DTMOS). DTMOS threshold voltage drops as gate voltage is raised, resulting in a much higher current drive than regular MOSFET at low Vdd. On the other hand, Vt is high at V,, = 0, thus the leakage current is low. Suitability of this device for ultra low voltage operation is demonstrated by ring oscillator performance down to Vdd = 0.5 v.

In this paper, we experimentally address the effect of a wide range of parameters on the high-field transport of inversion-layer electrons and holes. The studied parameters include substrate doping level, surface micro-roughness, vertical field strength, nitridation of the gate oxide, and device channel length. We employ special test structures built on Silicon-On-Insulator (SOI) and bulk wafers to accurately measure the high-field drift velocity of inversion-layer carriers. Our findings point to electron velocity overshoot at room temperature, dependence of electron and hole saturation velocities on nitridation of the gate oxide, dependence of the high-field drift velocity on the effective vertical field, and relative insensitivity of electron and hole mobility and saturation velocity to moderate surface roughness.

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