Interplay of Short-Channel and Narrow-Width Effects in FDSOI Transistors at Cryogenic Temperatures

The fully depleted silicon-on-insulator (FDSOI) technology has been a preferred choice for cryo-CMOS IC designers, but the combined effects of scaling both channel length and width, along with temperature variations, have not been extensively explored in the context of super low threshold voltage (SLVT) device technology. The key device figures of merit (FOMs), including threshold voltage (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>th</roman></sub>), drain-induced barrier lowering (DIBL), subthreshold swing (SS), transconductance (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>m</i></sub>), and ON-resistance (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>ON</roman></sub>), exhibit varying behaviors under changes in temperature and device scaling. Specifically, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>th</roman></sub>, DIBL, and SS degrade in narrow-width devices at lower temperatures, while <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">I</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>ON</roman></sub>, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>m</i></sub>, and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><roman>ON</roman></sub> improve. For short-channel devices, the FOMs behave similar to their room-temperature counterparts, but with a temperature-dependent offset at cryogenic temperatures. The underlying temperature-dependent effects at cryogenic temperatures are further analyzed using TCAD simulations at 8 K and room temperature (RT).