Silicon nitride deposition using N2-rare gas radio-frequency afterglows

Abstract

Summary form only given. Remote plasma chemical vapor deposition (RPCVD) is being used to form silicon nitride films. In the RPCVD process, high-energy ions and electrons do not come into contact with the silane reactant. Previous researchers have indicated that this is important for the formation of low-hydrogen-content silicon nitride films and is the key difference between remote plasma deposition and immersion plasma deposition. Experiments have been coordinated with theoretical modeling so that experimental parameters can be chosen to promote the formation of Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> precursors selectively. The model of the He-N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> discharge and afterglow includes the first two He metastables, a lumped He <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">*</sup> state, He <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> , and dimer metastables and ions. An important but uncertain rate is that for dissociation by <e1 xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</e1> - <e1 xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</e1> energy pooling, which depends on the vibrational manifold population. A rate for this process has been extracted from comparison of the model with published measurements of N and N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (A) production in pure N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> discharges. Ar-N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mixtures are of special interest because Ar( <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) and Ar( <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ) efficiently and selectively excite N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (A). It is shown that the Ar metastables that arrive in the deposition region are created not in the discharge, but in the afterglow via recombination of dimer ions