Characterization of BPSG films using Neutron Depth Profiling and Neutron/X-ray Reflectometry.

Borophosphosilicate glass (BPSG) films with a nominal thickness of 200 nm on Si wafers have been characterized using Neutron Depth Profiling (NDP) and neutron and x-ray reflectometry at the NIST Center for Neutron Research. NDP measures the total boron concentration and distribution. The x-ray reflectivity provides information on the thickness and density of the thin surface oxide layer and the density of the thick BPSG layer, whereas neutron reflectivity reveals the thickness of the BPSG layer. A more complete picture can be established to identify problems in semiconductor fabrication processes that cause undesirable dopant concentration and distribution, or density variations due to doping or implants. We report a first comparison of complementary information on the BPSG films obtained using the three techniques. [ABSTRACT FROM AUTHOR]