Modeling and Optimization of Three-Dimensional Interdigitated Lateral p-i-n Photodiodes Based on In0.53Ga0.47As Absorbers for Optical Communications

Access networks such as Fiber-to-the-Home based on passive optical networks (FTTH-PON) are experiencing a paradigm shift where these ‘last-mile’ networks are experiencing the need to provide converged services to the end-user at home. Triple-play services such as data and voice operating at the optical wavelength, ┣=1310 nm as well as video (┣=1550 nm) at a minimal speed of 2.5 Gbps are demanded to achieve an all-optical-network revolution (Kim, 2003; Lee & Choi 2007). It is estimated that in 2011, there will be 10.3 million FTTH households in the USA alone (Lee & Choi 2007). Thus, there arises a need to produce optical components which can be fabricated easily and in a cost-effective manner to cater for this ever-increasing demand. The development of interdigitated lateral p-i-n photodiodes (ILPP) based on In0.53Ga0.47As (InGaAs) absorption layer can be achieved using cheap and easy CMOS fabrication techniques such as diffusion and ion implantation. This can cater for the ever increasing demand of fiber-to-the home passive optical access networks (FTTH-PON) operating at a minimal speed of 2.5 Gb/s. The InGaAs ILPP which converts optical signals to electrical signals in the optical receiver has advantages compared to other photodiode structures because it has a high-resistance intrinsic region thus reducing Johnson noise, has low dark currents, permits a large detection area along with a low device capacitance, and can be monolithically integrated with planar waveguides or other devices. This chapter summarizes our key results on the modeling, characterization and optimization of ILPP based on In0.53Ga0.47As absorbers for optical communications. A three dimensional model of ILPP InGaAs operating at the optical wavelength, ┣ of 1.55 μm was developed using an industrial-based numerical software with a proposed fabrication methodology using spinon chemicals. New parameters for three different carrier transport models were developed and the proposed design was characterised for its dark and photo I-V, responsivity, -3dB frequency and signal-to-noise ratio (SNR) values. Statistical optimization of the InGaAs ILPP model was executed using fractional factorial design methodology. Seven model design factors were investigated and a new general linear model equation that relates the responsivity to significant factor terms was also developed (Menon, 2008; Menon et al.,2008a; Menon et al., 2008b; Menon et al. 2009)