Johannes Baumgartl

Uniformity improvement for 200 mm APCVD epitaxial Si film by retrofit of Applied Materials Epi Centura

An upgrade kit for the 200 mm Applied Materials Epi Centura was released. The retrofit includes an alignment tool for the setup of the process kit, a motorized lift as well as a new susceptor design. The hardware parts were installed in an APCVD (Atmospheric Pressure Chemical Vapor Deposition) production tool and tested in a production environment. The upgrade kit enables a reduction of the total range (max-min value) of the epi film thickness profile and a stable repeatability of the deposition process. A qualitative assessment of the new hardware during the production of an electrical device was carried out by analyzing sigma values of a PCM (Process Control Monitoring) parameter which is highly sensitive to variations in the epi thickness. The sigma of the PCM parameter from several lots, processed prior to the retrofit of the chamber and processed in the same chamber in the retrofitted state were compared and a reduction of the sigma value was observed when using the upgrade kit for the epi deposition.

Air Gap CV measurement for doping concentration in epitaxial silicon

Epitaxial silicon layers with low and intermediate resistivity were investigated with a contact-free capacitance versus voltage method. The low resistivity sample with 0.15 Ohm cm had long-term repeatability and reproducibility over 3 days with a fractional standard deviation of 0.8%. The intermediate resistivity epi layer with 6.2 Ohm cm had a long term repeatability with a fractional standard deviation of 0.16%. The fully automated CV tool measures with an electrode 0.5 μm above the wafer surface. A particle detection system ensures that there are no defects at the measurement site. This non-contact method has clear advantages over conventional methods such as mercury-CV or four-point-probe for determining doping concentration and doping depth profiles.