Investigation of the dark electrical characteristics of the lateral metal–semiconductor–metal photodetectors using two‐dimensional numerical simulation

Abstract

SUMMARYA detailed investigation of the dark electrical characteristics of the lateral metal-semiconductor-metal (MSM) structures is carried out using a two-dimensional numerical simulation based on the drift-diffusion model. The model includes image force barrier lowering and current-dependent recombination velocities at the Schottky contacts. The simulation was used to examine the details of the depletion region, the electric field distributions, and the current path in the active region of the planar structure. The obtained results were shown to be very helpful to understand and to explain various behaviours seen in the characteristics of the metal-semiconductor-metal (MSM) structures. The dark I-V characteristics of the structure were also calculated and compared with published experimental data. The results reveal the importance of the image force lowering on the characteristics and the hole injection at the forward contact beyond the flat band voltage.

Theoretical study of the DC and transient characteristics of a lateral Schottky barrier photodiode for application as high‐speed photodetector

“…These features observed are closely correlated to the pace of expansion of the depletion region within the active layer of the structures. A detailed discussion of the expansion of the lateral depletion region and its dependence on the applied bias was given in for the MSM structure; similar dependence is expected for the LSBPD; the first slow and then fast increase observed in the photocurrent characteristics of both structures are in full agreement with the expansion of depletion region reported in the paper. The last slow increase of the photocurrent in the MSM structure only arises because of the blocking barrier in the anode region, which does not exist in the LSBPD structure.…”

“…The resulting system of nonlinear algebraic equations can be written in matrix form as where F ψ , F n , and F p represent the Poisson's equations, the electron, and the hole continuity equations, respectively, and φ n and φ p are the quasi Fermi potential for electrons and holes. The details of the methodology employed to solve the system of equations given in are presented in , the transient problem is solved using the fully implicit method. The system is solved for the potential and carrier concentration profiles, from which the variables of interest are computed.…”

“…where F ψ , F n , and F p represent the Poisson's equations, the electron, and the hole continuity equations, respectively, and φ n and φ p are the quasi Fermi potential for electrons and holes. The details of the methodology employed to solve the system of equations given in 6 are presented in [27], the transient problem is solved using the fully implicit method. The system 6 is solved for the potential and carrier concentration profiles, from which the variables of interest are computed.…”

Performance enhancement of ZnO‐based MSM photodiodes by optimizing structure parameters

“…Poisson's Equation and the current continuity equations for electrons and holes, Equations and , are scaled, discretized, and solved numerically for the electrostatic potential and the carrier concentrations within the unit cell, from which the relevant electrical characteristics of PDs are evaluated. The details of the incorporated boundary conditions at the Schottky contacts and the methodology employed to solve the above‐mentioned system of equations were presented in the studies of Debbar . Table shows the ZnO thin film's parameters used in the simulation.…”

“…Therefore, a thorough investigation is crucial to find the necessary compromise between these parameters in order to design an MSM‐PD with optimal detector performance. A number of theoretical and experimental studies have been reported that investigate the influence of the structure's parameters in an endeavor to improve the ZnO‐based UV‐PD performance. Unfortunately, in these works, only one or few parameters were considered, and their effects were analyzed for a particular performance feature while ignoring their effects on other characteristics.…”