A High Yield Manufacturable BiFET Epitaxial
Profile and Process for High Volume Production
M. Sun, J. Li, P. Zampardi, R.
Ramanathan, A. G. Metzger, C. Cismaru, V. Ho, and L. Rushing
Skyworks Solutions, Inc.,
K. S. Stevens, M. Chaplin,
and R. E. Welser
Kopin Corporation,
The integration of FET in the conventional GaAs HBT process (BiFET) has
provided an additional degree of freedom in the design of advance bias circuits
in GaAs Power Amplifier and Analog/Mixed Signal applications. This paper discusses the development of a GaAs
based BiFET technology, including the epitaxial profile and process controls to
achieve high fab yield and manufacturability.
Epitaxial profile that integrates an HBT and a MESFET on the same GaAs
substrate and Capacitance-Voltage profiling for quality control are discussed. Influence of various fabrication process steps
on FET parameters and the process optimization steps are presented. Through such careful process control
procedures, high DC probe yield for the BiFET designs has been demonstrated.