PHYSICAL AND OPTICAL-PROPERTIES OF AN ANTIREFLECTIVE LAYER BASED ON SIOXNY

SiOxNy based materials were deposited at low substrate temperature (30 0 degrees C) and low pressure (0.6 Torr) in a plasma enhanced chemical vapor deposition reactor. The precursor gases were nitrous oxide (N2O ) and silane (SiH4); the ratio of the two-gas concentration N2O/SiH4 = alpha was a critical determinant of film structure and composition. A n extensive analysis of SiOxNy based materials was carried out using F ourier transform infrared, and Rutherford backscattering, and Auger an d ellipsometric spectroscopies. The two-phase structure of this materi al was deduced. This structure favors a high silicon film concentratio n and provides a sufficiently absorbing layer at photolithographic wav elengths (365, 248, and 193 nm). Thanks to its optical and physical pr operties silicon oxynitride constitutes a good antireflective layer fo r photolithographic applications. (C) 1997 American Vacuum Society.