| Monolithic silicon-based optical receivers are an attractive option for low-cost, high-volume applications where silicon BJT or MOSFET circuits, together with inexpensive short-wavelength light sources and multimode fiber, can provide an optical solution for local area networks (LAN), fiber-to-the home, and optical interconnects. For these applications high-volume, low-cost components are required. Hybrid III-V photodetectors can be used as photodetectors but a monolithic all-silicon receiver can further reduce the cost. Silicon bipolar-based receivers have the advantage of high transistor transconductance and operating speed. Silicon MOSFET-based receivers, on the other hand, offer a large manufacturing infrastructure, low power dissipation, and compatibility with the dominant transistor technology in both analog and digital applications. This dissertation presents design and fabrication of silicon based photodetectors and optical receivers in 130nm CMOS technology.; First, I present high-speed planar silicon P-I-N photodiodes that were fabricated on SOI substrates. The devices with 250nm finger spacing exhibited 15GHz and 8GHz bandwidths for devices processed on 200nm and 2000nm Silicon on insulator substrates respectively, at a reverse bias of −9V. Quantum efficiencies of 12% and 2% were measured on the 2μm and 0.2μm thick SOI, respectively. Capacitances of 40fF were measured while the dark current was 5pA for −3V bias and 500 μA for −9V bias.; The photodetectors were also monolithically integrated with a waveguide-grating coupler (WGC). For a Silicon on insulator thickness of 200nm, the quantum efficiency of the photodetector increased from 3% to 12% at 835nm when a WGC with 265nm period was used. The dark current for these devices was 10pA at −3V bias while the bandwidth was 4.1GHz (RC limited).; A monolithically-integrated silicon-based optical receiver is also presented. The devices were fabricated on 2μm-thick SOI substrates. The quantum efficiency of the photodetectors was ∼10% at 850nm. Sensitivities of −15.4dBm, −10.9dBm, 0.9dBm and 2dBm were measured for 3.125Gb/s, 5Gb/s, 6Gb/s and 8Gb/s, respectively, at a BER of 10−9. The dynamic range was 17.5dB, 13dB, and 3dB, at 3.125Gb/s, 5Gb/s, and 6Gb/s. The transimpedance gain of the receivers was in the range of 53.4dBΩ to 31dBΩ and the total dissipated power was between 10 and 35mW depending on the circuit design. |
