Application of flip-chip bonding techniques for Si based smart pixels

Abstract

Material and operational compatibility among processing elements, detectors, and modulators is critical issue in the implementation of smart pixels. This paper describes the hybrid integration efforts for MQW and PLZT modulator arrays with Si detectors and Si VLSI processing elements. Detectors and driver circuits compatible with the MOSIS process have been realized. An amplifier circuit has been designed to drive PLZT with a 35 V swing at 5 MHz. This is accomplished by using series connected transistors and a current-mirror-like structure to increase the breakdown voltage of the circuit. The combination of the driver and a reflective PLZT modulator can produce light modulation with a dynamic range of 600:1. Studies of the speed response of PLZT 9/65/35 show rise and fall times of 10 ns, limited by the drive circuitry. MQW modulators have been implemented by using InAlGaAs/InGaAs operating at 1.06 μm on GaAs substrates. This structure produces modulators that are compatible with Si detectors and flip-chip bonding with Si VLSI circuitry. Flip-chip bonded smart pixel arrays incorporating PLZT and MQW modulators and characteristics of simple optical links between the smart pixels have been studied.