Temperature-Dependent Characteristics and Electrostatic Threshold Voltage Tuning of Accumulated Body MOSFETs
A B M Hasan Talukder, Brittany N. Smith, Mustafa Akbulut, Faruk Dirisağlık, Helena Silva, Ali Gokirmak
Abstract
Narrow-channel accumulated body nMOSFET devices with p-type side gates surrounding the active area have been electrically characterized between 100 and 400 K with varied side-gate biasing ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {side}}$ </tex-math></inline-formula> ). The subthreshold slope (SS) and drain induced barrier lowering (DIBL) decrease and threshold voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{t}$ </tex-math></inline-formula> ) increases linearly with reduced temperature and reduced side-gate bias. Detailed analysis on a 27 nm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 78 nm (width <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> length) device shows SS decreasing from 115 mV/dec at 400 K to 90 mV/dec at 300 K and down to 36 mV/dec at 100 K, DIBL decreasing by approximately 10 mV/V for each 100 K reduction in operating temperature, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{t}$ </tex-math></inline-formula> increasing from 0.42 to 0.61 V as the temperature is reduced from 400 to 100 K. <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{t}$ </tex-math></inline-formula> can be adjusted from ~0.3 to ~1.1 V with ~0.3 V/V sensitivity by depletion or accumulation of the body of the device using <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {side}}$ </tex-math></inline-formula> . This high level of tunability allows electronic control of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{t}$ </tex-math></inline-formula> and drive current for variable temperature operation in a wide temperature range with extremely low leakage currents (<10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−13</sup> A).