Optically Controlled Silicon MESFET Fabrication and Characterizations for Optical Modulator/Demodulator

Abstract

Abstract-An optically controlled silicon MESFET (OPFET) was fabricated by diffusion process to enhance the quantum efficiency, which is the most important optoelectronic device performance usually affected by ion implantation process due to large number of process induced defects. The desired impurity distribution profile and the junction depth were obtained solely with diffusion, and etching processes monitored by atomic force microscope, spreading resistance profiling and C-V measurements. With this approach fabrication induced defects are reduced, leading to significantly improved performance. The fabricated OPFET devices showed proper I-V characteristics with desired pinch-off voltage and threshold voltage for normally-on devices. The peak photoresponsivity was obtained at 620 nm wavelength and the extracted external quantum efficiency from the photoresponse plot was found to be approximately 87.9%. This result is evidence of enhancement of device quantum efficiency fabricated by the diffusion process. It also supports the fact that the diffusion process is an extremely suitable process for fabrication of high performance optoelectronic devices. The maximum gain of OPFET at optical modulated signal was obtained at the frequency of 1 MHz with rise time and fall time approximately of 480 nS. The extracted transconductance shows the possible potential of device speed performance improvements for shorter gate length. The results support the use of a diffusion process for fabrication of high performance optoelectronic devices.

Analytical Model of Double Gate MOSFET for High Sensitivity Low Power Photosensor

“…3(b) shows the optical response for the ZnO-SiO 2 -Si system over a range from 0.25 µm to 1.5 µm. This type of behavior where maximum responsivity is obtained at lower wavelengths is also reported in [26][27][28][29][30]. As is clear from the Fig.…”

A Proposed Silicon Optical Electronic Integrated Circuit with Monolithic Integration of LED, OPFET and Receiver Circuit

“…The theory of operation for Silicon controlled optical MESFET as reported by [11] while its analytical modeling has been described in [12] for details. The electron-hole pair is generated when the semiconductor device like OPFET is illuminated by photons with energy greater than band-gap of Silicon and smaller than the energy band-gap of Indium tin oxide i.e.…”

“…A reasonable channel thickness is used in order to absorb the maximum optical radiation as well as to prevent the loss of photogenerated carrier. The peak responsitivity and maximum output voltage of the 13μm gate OPFET were found to be at 620nm and 1.0 MHz [11]. Figure-3 depicts the graphical sketch of OPFET optical response i.e.…”

“…is the quantum efficiency, λ is the wavelength in nm, h is the Plank's constant and q is the charge on electron. As the optical response reported by [11] the peak responsitivity is occurs at 620nm, so the above equation will be given in Eq. (4): … (4) So it shows that optically controlled silicon MESFET having high respositivity improves the quantum efficiency to 88% which is much higher than the older optoelectronic devices.…”

Process Considerations for 80-GHz High-Performance p-i-n Silicon Photodetector for Optical Interconnect

“…Optical interconnect includes not only the waveguide itself but also light-emitting diode (LED) or laser as the light source, modulator, and photodetector. Integration on silicon (Si) substrate is strongly pursued owing to cost-effectiveness and complementary metal-oxide-semiconductor (CMOS) process compatibility [2][3][4][5][6], which makes it essential to exploit Si-compatible materials, structures, and process architecture highly suitable to integration with Si ICs.…”