| The most researched material system for infrared imaging is HgCdTe. It boasts very high detectivity and quantum efficiency, yet it suffers from several major material and crystal growth problems, making the fabrication of HgCdTe focal plane arrays notoriously difficult. A very attractive alternative is the quantum well infrared photodetector (QWIP). QWIPs offer mature III-V growth technology and therefore excellent array uniformity and operability.; Since the readout integrated circuitry used in virtually all focal plane arrays is Si-based, a technique such as indium bump bonding is necessary to mate a III-V QWIP array to the processed Si wafer. This can become particularly cumbersome and unreliable for large focal plane arrays. If the growth of the QWIP structure could occur directly on the Si wafer, bump bonding can be eliminated, and QWIP arrays could be made with higher yield and lower cost. Moreover, the array would benefit from the higher thermal conductivity and mechanical strength of the Si wafer.; In this study, the growth and fabrication of GaInAs/InP QWIPs by LP-MOCVD is detailed. The GaInAs/InP material system was chosen because QWIPs fabricated from it have exhibited high responsivity and gain. To realize monolithic integration of QWIPs on Si, the following procedure was used: (1) optimization of QWIP performance on InP substrate with respect to the structural parameters of the QWIP, (2) epitaxy of highly mismatched III-V material on Si substrate with a low threading dislocation density, and (3) demonstration of QWIPs on Si substrate with the optimized structural parameters.; For GaInAs/InP QWIPs on InP substrate with optimized performance, a responsivity of 33.2 A/W has been achieved, which to our knowledge is the highest value reported for any QWIP in the λ = 8–9 μm range. By substituting GaInAsP in the quantum well, the cutoff wavelength is extended beyond 17 μm. The responsivities of GaInAs/InP QWIPs on Si substrate is equal with identical QWIPs on InP substrate up to biases of 1.5 V, and a responsivity of 1.0 A/W is measured at a bias of 3 V. This represents the first demonstration of an InP-based QWIP on Si substrate. |
