Defect Detection and Mitigation in Low Pressure PECVD Systems: Special Case of Nodule Formation in Densified SiNx Films.

Jeremiah Sires, Skyworks Solutions, Inc.

Extensive literature exists on  characterization of SiNx (silicon nitride) films based on C-V (Capacitance – Voltage) performance and hydrogenation of films, as well as the photoluminescent properties studied through various spectroscopy methodologies (Raman, SIMS and XPS).  However, few physical defect studies, particularly in low frequency PECVD (Plasma-Enhanced Chemical Vapor Deposition), can be found.  This study will discuss in detail the formation of nodules in densified N-rich (N/Si > 1.33) SiNx films deposited via LF PECVD on CZ polished Si substrates via the formation of K centers and resulting Si nanoclusters and surrounding nitrogen depletion zones within the film.  Additionally, three distinct defect mechanisms are isolated and procedures implemented to mitigate product exposure through detection methodology and determination of appropriate preventative hardware maintenance.

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