Two-dimensional device modeling and analysis of GaInAs metal–semiconductor–metal photodiode structures

Abstract

A two-dimensional self-consistent time-dependent simulation technique has been developed to investigate electron-hole transport processes in the active region of metal–semiconductor–metal (MSM) interdigitated photodiode structures and to analyze their high-speed response. The distribution of the electric field inside the MSM device is determined by numerically solving the two-dimensional Poisson’s equation by the modified fast elliptic solver method. A set of superparticles photogenerated at a particular wavelength is analyzed with a given initial distribution of the potential and given boundary conditions, and the evolution of the particles is traced in time through the active region of the MSM device. Circuit loading, electric field effects in the MSM structure with various finger separations, background doping, carrier trapping, and recombination are included in the simulation program. Owing to miniaturization of devices, the classical scaling laws lose their validity while various performance degrading effects appear. The simulations show that the main problem in MSM devices with a small contact separation is the low electric field penetration depth. This results in different electron and hole collection rates and in a poor response time. The trade-off between the high-speed response and the internal quantum efficiency is examined and ways to improve the high-speed response are indicated. Modeling results are compared with experimental data on Ga0.47In0.53As based MSM photodiodes.

Measurements of InGaAs metal–semiconductor–metal photodetectors under high-illumination conditions

“…As shown in Ref. 8, the hole-current contribution is about 1/5 of the total current. Hence, the hole current does not appreciably influence the FWHM.…”

“…Recently, a two-dimensional device model was used to investigate the temporal impulse response of GaAs MSM-PDs under highillumination conditions ͑ϳ200 pJ͒ 6,7 and the response of InGaAs MSM-PDs as a function of bias voltage for low optical pulse energy ͑Ͻ0.1 pJ͒. 8 In Refs. 6 and 7, simulations show that the impulse response of GaAs MSM-PDs is distorted, and the bandwidth and efficiency of the devices are reduced due to screening of the dark electric field at high optical excitation levels.…”

Solar-blind MSM-photodetectors based on Al x Ga1-x N heterostructures

“…10 and 11. This departure from the simple scaling is caused by space-charge effects due to non-linearities in the velocity-field behavior of the electrons and holes (Averine et al 1996).…”

“…One then can expect modification of the internal electric field that governs the carrier drift processes in these structures. For that reason we have also used a two-dimensional time-dependent simulation technique (Averine et al 1996) to investigate electron-hole transport processes in the active region of GaN-based MSM-PD and analyze detector high-speed response at different energy levels of optical illumination. We also used this model to compare dynamic range potentialities of GaN-based MSM detector with that of on GaAs.…”

МПМ детектор видимого диапазона длин волн на сверхрешетке ZnSe/ZnTe второго типа

“…В качестве базовой структуры для исследова-ний были выбраны поверхностно-барьерные планар-ные диоды на основе выпрямляющего контакта в системе металл−полупроводник−металл (МПМ ди-од) [8][9][10]. МПМ детекторы изготовлены на сверхре-шетке ZnSe/ZnTe, структура и толщины слоев которой приведены на pис.…”