Journal of Vacuum Science & Technology B, Vol.18, No.3, 1663-1667, 2000
Process control of high volume pseudomorphic high electron mobility transistor and metal-semiconductor field effect transistor molecular beam epitaxy production using temperature-dependent photoluminescence
In this article we report the nondestructive photoluminescence (PL) techniques to monitor and control high volumes of pseudomorphic high electron mobility transistors (PHEMT) and metal-semiconductor field effect transistors (MESFETS) molecular beam epitaxy (MBE) production. By studying the PL line-shape we found that the correlation between the intensity or the peak position and the doping level is much poorer than that between full width at half maximum (FWHM) and doping level. For the bulk doping layer the minimum detectable level is around 5 X 10(16) cm(-3) by 77 K PL. The FWHM correlation between bulk doping and the active doping layer from product wafers has been determined. Furthermore, a three-sigma PL control chart of the MESFET product wafer, which monitors nondestructively with about 5% accuracy, has been setup. After a detailed analysis of the variations of different parameters against PHEMT structure information obtained using x-ray diffraction and Hall effect, we found a close correlation between the PL spectra and the PHEMT structures. The successful PL monitoring of AlGaAs, which is a key factor in determining PHEMT quality and device performance, shows useful information on AlGaAs quality and doping level to guide PHEMT production. By applying the process control method the mass production and device performance shows that the quantum well thickness can be controlled within 1.0%, charge density within 1.5% and the Al and In compositions within 0.2% with over 98% production wafer line yield and over 85% device package yield.
Keywords:DX CENTER