Enhanced Visible Light Sensitivity by Gold Line-and-Space Grating Gate Electrode in Thin Silicon-On-Insulator p-n Junction Photodiode (original) (raw)
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Material Dependence of Metal Grating on SOI Photodiode for Enhanced Quantum Efficiency
IEEE Photonics Technology Letters, 2000
Material dependence of line-and-space metal grating among gold, silver, and aluminum, is experimentally investigated for a 100-nm-thick silicon-on-insulator p-n junction photodiode in terms of enhanced light sensitivity. It is found that light sensitivity in visible long-wavelength region is enhanced with any grating material, and the peak wavelengths, which are determined by the grating period, are not much affected by the material. The relationship between the peak wavelength and the grating period is explained theoretically. The results indicate that the grating material can be selected from these materials by taking into account the short-wavelength sensitivity and compatibility with applications.
Enhancement of SOI Photodiode Sensitivity by Aluminum Grating
ECS Transactions, 2013
Aluminum grating was applied to silicon-on-insulator (SOI) pnjunction photodiode to increase the light sensitivity. For 100-nmthick diode, quantum efficiency (QE) of 26% (15 enhancement) was attained at the wavelength of 700 nm. Wavelengths of the QE peaks for various grating pitches and light incident angles were examined, and it was confirmed that the coupling between the diffracted light from the grating and the propagation modes in the SOI slab waveguide caused the enhancement.
IEICE Electronics Express
Angle-sensitive pixel (ASP) made of silicon-on-insulator (SOI) p-n junction photodiode (PD) and aluminum (Al) line-and-space (L/S) grating gate electrode is proposed, and the incident angle dependence of spectroscopic quantum efficiency (QE) in visible light range are evaluated experimentally. Good agreement between measured peak wavelengths and theoretical ones was successfully obtained for various grating periods and two linearly-polarized lights. The proposed ASP would contribute to the advanced imaging with incident angle information.
Applied Physics Letters, 2011
The sensitivity of silicon-on-insulator (SOI) lateral p-n junction photodiode was enhanced by attaching gold (Au) nanoparticles. This was confirmed by comparing I-V characteristics with and without Au nanoparticles at various substrate voltages. Twofold enhancement was attained in the visible wavelength region when the substrate was biased to positive. The substrate bias changed the area of depletion layer in SOI, and the light scattering by Au nanoparticles effectively enhanced the sensitivity when the area of depletion layer was small.
IEEE Transactions on Nanotechnology, 2000
photodiode is investigated. The SOI-MOS photodiode has the advantages such as high-speed operation, large voltage gain per electric charge, and small dark current. However, its light sensitivity is usually very low due to the small volume of light absorption. In order to enhance the light sensitivity, a surface plasmon (SP) antenna is adopted. The SP antenna is constructed with periodic metallic structure, and can convert the incident light to optical near-field around the surfaces of the antenna. By replacing the MOS gate with the SP antenna, it becomes possible to enhance the light absorption while keeping the advantages of SOI-MOS photodiode. This paper focuses on the visible light absorption in the SOI-MOS photodiode with the SP antenna. The structural conditions for high absorption efficiency and single-peaked spectroscopic characteristics, polarized light response, and resonance mechanisms are clarified by electromagnetic simulations using the finite-difference time-domain (FDTD) method.
Highly efficient semiconductor grating structure for SOI optical circuits
Optik, 2017
This paper explores high efficiency of semiconductor grating structure at wavelength, 1550 nm for silicon on insulator (SOI) optical circuits. Here semiconductor grating structure is realized by the combination of silicon and compound semiconductor materials, where compound semiconductor gratings are envisaged by indium phosphide, Al80Ga20As and Al42Ga58As. Different types of losses in terms of absorption, reflection and diffraction including polarization are cogitated to investigate the efficiency of grating SOI structure at wavelength, 1550 nm. Interestingly, the absorption loss of above semiconductor grating is found to be zero at the above wavelength. Also the simulation was accomplished using plane wave expansion method, which leads to zero reflectance for the aforementioned structures at same wavelength. Simulation is also made for diffraction and polarization losses of above three semiconductor grating SOI structures. Simulation results reveal that diffraction efficiency is 1, (diffraction loss is zero) with respect to detune from Bragg's angle which ranges from-12 0 to +12 0. Additionally, the proposed structures encountered polarization losses .Present simulation result showed that polarization efficiency is more than 90% (polarization loss is less than 10%)in silicon-indium phosphide (Si-InP) ,silicon-Al80Ga20As (Si-Al80Ga20As) and silicon-Al42Ga58As (Si-Al42Ga58As) grating SOI structures with respect to same deviation. Since absorption, reflection and diffraction losses are zero, the overall transmitted efficiency depends on polarization efficiency and finally , with the combination of both absorption, reflection ,diffraction and polarization loss ,it is inferred that overall transmitted efficiency of semiconductor grating SOI structure is more than 90% with respect to same angle.
IEEE Transactions on Electron Devices
Photodetectors (PDs) used in communication systems require ultrafast response, high efficiency, and low noise. PDs with such characteristics are increasingly in demand for data centers, metro data links, and longhaul optical networks. In a surface-illuminated PD, high speed and high efficiency are often a tradeoff, since a high-speed device needs a thin absorption layer to reduce the carrier transit time, whereas a high-efficiency device needs a thick absorption layer to compensate for the low absorption coefficient of some semiconductors such as Si and Germanium (Ge) or SiGe alloys at wavelengths near the bandgap. In this part of this review, we present the recent efforts in enhancing the photon-material interactions by using low-dimensional structures that can control light for more interaction with the photoabsorbing materials, slow down the propagation group velocity and reduce surface reflection. We present recent demonstrations of high-speed PDs based on nanostructures enabled by both synthetic bottom-up or transformative top-down processing methods. In particular, we detail a CMOS-compatible ultrafast surfaceilluminated Si PD with 30-ps full-width at half-maximum, and >50% efficiency at 850 nm. A complementary discussion on device challenges and the integration of low-dimensional structures will be presented in the part II of this review.
Broadband absorption enhancement of thin SOI photodiode with high-density gold nanoparticles
Optical Materials Express, 2014
We demonstrated the quantum efficiency (QE) of silicon-oninsulator (SOI) photodiode was enhanced in visible wavelength region by using gold (Au) nanoparticles. The photons plasmonically scattered by Au nanoparticles couples with the waveguide mode in SOI, and are absorbed efficiently. Optimum size and density of Au nanoparticles have been investigated by 3-D FDTD simulations for sensitivity improvement. The highest enhancement factor of the absorption efficiency in 100-nm-thick SOI is obtained by periodically attaching Au nanoparticles of about 140 nm in diameter and 1.7 × 10 9 particles/cm 2 in density. Two-fold enhancement in QE was experimentally achieved in visible by the SOI photodiode with randomly arranged Au nanoparticles of the size and density close to the optimized values.