Monolithic Integration of Rectifiers and Drivers for low power SSL applications on a Rigid to Flex Substrate

Abstract

Solid State Lighting (SSL) is one of the prominent light sources for future lighting applications with benefits such as high energy savings, long lifetimes and high efficiency. The main drawback in solid state lighting system is that the total initial cost of the system is high for large scale production. Packaging and electronics components in the system account to about 60% of the total cost. Silicon based wafer level packaging offers great advantages for large scale cheap production. Furthermore it also helps to create to create miniaturized and multifunctional system with integrated electronics with LEDs. In this thesis, a novel schottky diode in BiCMOS having high current conduction and high breakdown is designed and fabricated. A monolithically integrated rectifiers composed with four schottky diodes is presented. The rectifiers designed using schottky diodes are fabricated in a simple and low cost DIMES BiCMOS7 process. A detailed modeling and simulation of schottky diodes in a standard BiCMOS process is done to derive design parameters to achieve high current and high breakdown voltage. It has been found that with guard rings and a n well doping concentration determined by a phosphor dose of 6e12, schottky diodes with a breakdown voltage of 27V and forward current of 1A at 0.68V are fabricated in this process. A complete design, fabrication, characterization and spice modeling of the schottky diodes are presented. NMOS and NPN bipolar transistor fabricated in the BiCMOS process are characterized and modeled. A basic linear and switch mode driver using the devices fabricated in the BiCMOS process is analyzed. A design proposal for integrating the rectifiers and drivers on a Rigid to flex substrate is presented. The developed concept offers great advantage for wafer level integration of SSL system to reduce cost and create smart multifunctional miniaturized products.