Annealing Effects on Silicon Oxynitride Layer Synthesized by N Plasma Immersion Ion Implantation

Abstract

A silicon oxynitride layer was obtained on a polished silicon wafer surface by nitrogen plasma immersion ion implantation. Oxygen is provided by the residual gas in the implantation chamber (base pressure of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3 times 10^-5 hboxmbar$</tex> ) and is also implanted as the main impurity. As-implanted Si samples were analyzed by high-resolution Auger electron spectroscopy (AES), which indicated the formation of a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$hboxSiO_ xhboxN_ y$</tex> layer of about 30 nm with varying <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$x$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$y$</tex> , along the depth of the treatment layer. AES also provided concentration profiles of the implanted elements at the as-implanted stage. Annealing of samples from a batch of such oxynitrided Si samples was carried out at different temperatures ranging from 200 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$^circhboxC$</tex> to 1060 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$^circhboxC$</tex> . The AES analysis of these annealed samples indicated a significant escape of the implanted nitrogen atoms (starting already at 200 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$^circhboxC$</tex> ), but even at 1060 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$^circhboxC$</tex> , there was a very thin (about 12 nm) remaining layer of the silicon oxynitride, which is probably in crystalline form. Results from high-resolution X-ray diffraction measurements also corroborate the aforementioned results.