Trace moisture in ammonia

摘要

Detection of moisture contamination in hydride gases, such as ammonia used for epitaxial growth, has become a significant concern for manufacturers of Ⅲ-Ⅴ compound semiconductors. The presence of moisture in NH_3 can negatively affect device properties, such as minority-carrier lifetimes and luminescent efficiency in light-emitting diodes. Tunable diode laser spectroscopy (TDLAS) has emerged as a potential solution for trace moisture detection in ultrahigh-purity gases. Tests show TDLAS is a viable on-line process analyzer in NH_3 applications and an alternative to Fourier transform infrared (FTIR) spectroscopy.