A modulation-doped field-effect transistor-based optoelectronic integrated circuit receiver for optical interconnects

The success of optical interconnects for computer communications depends critically on the development of a viable monolithic optoelectronic integrated circuit (OEIC) technology. A key component of any lightwave communication system is the optical receiver/preamplifier which converts the low-level optical signals into amplified electrical signals. This thesis describes the design, fabrication, and characterization of an OEIC receiver based on submicron pseudomorphic modulation-doped field-effect transistors (MODFETs) and a metal-semiconductor-metal photodetector (MSM-PD). Extensive discrete electronic and photonic device results are presented and related to receiver design. The performance of the overall receiver and individual circuit elements is reported and compared with theory.;Pseudomorphic MODFETs based on the InGaAs/GaAs strained-layer material system are chosen due to their superior performance compared to the lattice-matched GaAs system. The design and fabrication of high-speed MODFETs for integrated circuits are presented. Thick, highly doped cap layers and selective gate recess etching are the keys to achieving uniform high-performance MODFETs. The microwave characteristics are studied using a delay time approach to separate out parasitic effects. A conventional GaAs MSM is investigated and is found to be dominated by surface effects which lead to large dark currents and low-frequency gain. Two different MSM designs are presented which eliminate or greatly reduce these anomalous effects. A submicron MSM-PD is shown to exhibit a bandwidth of 70 GHz using a novel integrated photoconductive sampling technique.;The design and characterization of a transimpedance preamplifier are described in detail, taking into account such factors as bandwidth, noise, and circuit complexity. An active feedback resistor consisting of a common-gate FET is utilized in the amplifier design. This FET, however, is found to contribute a large parasitic capacitance to the input of the amplifier which limits the bandwidth. Nevertheless, a 3-dB bandwidth of greater than 3 GHz and as high as 4.5 GHz is measured for the overall receiver.