MODELING AND SIMULATION OF SCHOTTKY BASED PHOTODETECTOR FOR RESPONSIVITY IMPROVEMENT BY UTILIZING NANOSTRUCTURE

• Main Author: Surawijaya, Akhmadi
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83231
• Institution: Institut Teknologi Bandung

In optical communications technology, which is currently developing rapidly, photodetectors in the Near Infra Red spectrum are needed, however, silicon-based devices have the weakness of being transparent at NIR wavelengths. Silicon-based photodetector devices generally have low responsiveness due to the low absorptivity of light at NIR wavelengths. Several attempts to increase responsiveness are by utilizing plasmonic effects or by using Schottky contacts, but these efforts are hampered by high series resistance so that the resulting photodetector current is small, and the response time is longer. These constraints cause the Figure-of-Merit value of Silicon-based photodetectors to be low. To overcome the problem of low FoM values, this research aims to increase the responsiveness value of the device and response time where the device application is a Photonic Integrated Chip which generally pursues conditions of low power consumption and high data transfer. This research focuses on an optical wavelength of 850 nm with the design of a silicon-based photodetector device with a lattice structure. The lattice structure allows light to be more concentrated in the lattice structure based on the Leaky Mode Resonance concept. The device structure was fabricated using the Metal Assisted Chemical Etching method. The device is then simulated using ANSYS Lumerical software which includes photonic (FDTD), electrical (CHARGE) and Photonic Integrated Circuit (Interconnect) simulations. Light absorbance at a wavelength of 850 nm is optimized by optimizing the structure's duty cycle using the swarm optimization method. On the optimized structure, simulations are then carried out to calculate the photocarrier generation rate which is then used in electrical simulations to calculate dark current and responsiveness. The effect of Internal Photo Emission on the metal structure is also considered in the overall current calculation. In the electrical simulation, transient characteristic simulations are also carried out to calculate the time and frequency response of the device. The steady state and transient characteristics of the device are then used to simulate device behavior on a simple photonic integrated chip model. From the simulation results, it is obtained that the photodetector device has a responsiveness of 2.22 A/W with a bandwidth of 16.70 GHz which can be applied to photonic chips with data transfer reaching 50 Gbps with an Optical Signal to Noise Ratio of 17.90 dB, the resulting FoM is 37,009 The novel device designed in this study has a device area that is smaller than similar devices reported in other studies with responsiveness and FoM output that is one magnitude larger.