Sub-ppb detection limits for hydride gas contaminants using GC-ICP-QQQ

Version 1

    Application note

    Semiconductor and petrochemical

     

    Abstract

    Hydride gases, such as phosphine and arsine, are important contaminants in process chemicals used in both the petrochemical and semiconductor industries. For example, the presence of phosphine, arsine, hydrogen sulfide and carbonyl sulfide in polymer grade ethylene or propylene can have a deleterious effect on catalysts used in the production of polypropylene plastics. Accurate data on the concentrations of these contaminants at trace levels enables prediction of catalyst lifetime and minimizes production downtime.

    In the semiconductor industry, phosphine is used as a precursor for the deposition of group III-V compound semiconductors, and as a dopant in the manufacturing of semiconductor devices, such as diodes and transistors. In the case of group III-V compound materials, such as indium phosphide (InP), absence of other hydride dopant impurities e.g., silane, germane or hydrogen sulfide (and moisture) is critical, as they can have a profound effect on the performance of the final device. In particular, incorporated sulfur from hydrogen sulfide and carbonyl sulfide may affect the electrical properties ofthe device, such as carrier concentration and electron mobility. In the case of arsine, which is used in the manufacture of high electron mobility transistors (HEMTs) and field effect transistors (FETs), product performance can be adversely affected by the presence of germane.

    To date, measurement of these contaminants at ppb levels has been sufficient, but increasing competition within the industry and evolving performance criteria are pushing specifications ever lower. In addition, high purity gas manufacturers often require analytical detection limits 5–10 times lower than reported specifications. Earlier generation quadrupole ICP-MS (ICP-QMS) detectors were capable of measuring sulfur and silicon species at the 10 ppb level. More recently, the Agilent 7900 ICP-MS has demonstrated the ability to measure these elements at the 1–2 ppb level. In anticipation of increasing industry demand for even lower levels, a new high sensitivity GC-ICP-MS method using the Agilent 8800 Triple Quadrupole ICP-MS (ICP-QQQ) was developed for this application.

     

    Publication number: 5991-5849EN

    Publication Date: May 28, 2015

     

    http://www.agilent.com/cs/library/applications/5991-5849EN_AppNote_8800_ICP-QQQ_hydride_gas_v5.pdf