Large array of GaAs modulators and detectors flip-chip solder bonded to silicon CMOS using InGaP as the selective etch stop for GaAs substrate removal

Abstract We demonstrate the integration of a large (64 × 68) p-i(MQW)-n GaAs diode array to a silicon CMOS chip, using flip-chip solder bump bonding techniques together with concomitant GaAs substrate removal. The capability of removing a relatively large area of GaAs substrate cleanly and uniformly is attributed to the introduction of a new selective etch stop with a smooth isotropic etchant for the GaAs substrate removal. The presence of the lattice matched In 0.49 Ga 0.51 P selective etch stop layer has no detrimental effect on the performance of the GaAs AlGaAs optical detector/modulator diodes, which gives the chip the large I O count of 4352.