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

A B S T R A C T
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.