P A P E R    T I T L E
Characterization and Control of Epitaxial Material for HBT Manufacturing

A U T H O R  /  C R E D I T S
I. D. Calder, E.M. Griswold and G. Hillier
Advanced Technology Laboratory, Nortel Networks, P.O. Box 3511, Stn. C
Ottawa, Ontario, Canada K1Y 4H7
Phone: (613) 763-5442, e-mail: icalder@nortelnetworks.com

An extensive toolkit of characterization techniques has been assembled to monitor epitaxial growth of GaAs and GaInP layers for HBT fabrication. Resistivity and particle count measurements are made on every wafer; photoreflectance spectroscopy (PR) provides rapid feedback on composition and GaAs doping levels, and x-ray diffraction rocking curve analysis (XRD) of a grown-in superlattice structure supplies growth rate data. Selected wafers undergo SIMS and SEM analysis to determine thickness, doping, and composition of all layers. Thick GaInP and p+ GaAs calibration layers provide information on composition and carbon doping, through photoluminescence (PL), Hall effect, and XRD. Together, PL, PR, and XRD correlate GaInP ordering with reactor-to-reactor variations in material properties. This toolkit not only measures all important growth parameters, but also provides some redundancy to check measurement consistency, a basis for SPC, and correlations with device characteristics.