2011/08/25 by Aneesh Nainani, Toshifumi Irisawa, Ze Yuan +6
Engineering · Materials Science · #Semiconductor materials and devices #Advancements in Semiconductor Devices and Circuit Design #Electronic and Structural Properties of Oxides
paper · doi:10.1109/ted.2011.2162732
While there have been many demonstrations on n-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) in III-V semiconductors showing excellent electron mobility and high drive currents, hole mobility in III-V p-channel MOSFETs (pMOSFETs) has traditionally lagged in comparison to silicon. GaSb is an attractive candidate for high-performance III-V pMOSFETs due to its high bulk hole mobility. We fabricate and study GaSb pMOSFETs with an atomic layer deposition Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> gate dielectric and a self-aligned source/drain formed by ion implantation. The band offsets of Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> on GaSb were measured using synchrotron radiation photoemission spectroscopy. The use of a forming gas anneal to passivate the dangling bonds in the bulk of the dielectric was demonstrated. The density of interface states <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">it</sub> was measured across the GaSb band gap using conductance measurements, and a midband-gap <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">it</sub> of 3 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> /cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> eV was achieved. This enabled pMOSFETs with a peak hole mobility value of 290 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /Vs.