Abstract

Crystalline silicon nitride (Si₃N₄) is of considerable interest commercially, e.g., as a passivating layer in the microelectronics industry and in the construction of advanced heat engines. The high-temperature, nitriding processes normally used in the manufacture of this ceramic yield materials in which the ratio of the α- and β-Si₃N₄ polymorphic, crystalline modifications varies considerably depending on the actual synthetic conditions employed. Almost ten years ago, Luongo showed that IR spectroscopy could readily be used for the rapid, quantitative identification of crystalline α- and β-Si₃N₄ in the presence of each other, despite the very close structural similarities between the two polymorphic phases. The IR method was based on determining the ratio of the absorbances (<i>I</i>₆₈₅/<i>I</i>₅₇₈) of two characteristic marker bands which appear at 685 (α-Si₃N₄) and 578 cm⁻¹ (β-Si₃N₄). A graph for determining the relative amounts of the two polymorphic phases in the presence of each other in an unknown sample was published as part of Luongo's paper.

Infrared Spectroscopy at High Pressures: Polarized Spectra of Single Crystals of Acetonitrile

R. J. Jakobsen and Y. Mikawa
Appl. Opt. 9(1) 17-22 (1970)

Improving optical properties of silicon nitride films to be applied in the middle infrared optics by a combined high-power impulse/unbalanced magnetron sputtering deposition technique

Bo-Huei Liao and Chien-Nan Hsiao
Appl. Opt. 53(4) A377-A382 (2014)

Effect of Pressure on the Optical Rotatory Power and Dispersion of α-Quartz

M. B. Myers and K. Vedam
J. Opt. Soc. Am. 56(12) 1741-1745 (1966)

High Pressure Optics

A. Van Valkenburg
Appl. Opt. 9(1) 1-4 (1970)

Effects of bombardment on optical properties during the deposition of silicon nitride by reactive ion-beam sputtering

M. F. Lambrinos, R. Valizadeh, and J. S. Colligon
Appl. Opt. 35(19) 3620-3626 (1996)