Lowering of Schottky Barrier Height in a Vertical Pillar MOSFET by Deuterium Annealing

Abstract

The Schottky barrier height (Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> ) is lowered by high-pressure deuterium annealing (HPDA), in a vertical pillar (VP) metal-oxide-semiconductor field effect transistor (MOSFET). Typical device characteristics were comparatively studied before and after HPDA. A change of contact 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">C</sub> ) at a Schottky junction was also analyzed by using a transmission line method (TLM). Moreover, HPDA effects on the <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">C</sub> were characterized on different crystal orientations of silicon, which has a different number of traps. HPDA is more effective to lower the Φ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">B</sub> at (111) orientation than at (100) orientation because a greater number of interface traps can be passivated for an orientation with a high Miller index. Finally, a deuterium peak was physically profiled across the Schottky junction by use of time-of-flight secondary ion mass spectrometry (ToF-SIMS).