Optically Controlled Silicon MESFET Modeling Considering Diffusion Process (original) (raw)
Related papers
Journal of Semiconductor Technology and Science
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.
A two-dimensional (2D) analytical model for the potential distribution and threshold voltage of short-channel ion-implanted GaAs MESFETs operating in the sub-threshold regime has been presented. A double-integrable Gaussian-like function has been assumed as the doping distribution profile in the vertical direction of the channel. The Schottky gate has been assumed to be semi-transparent through which optical radiation is coupled into the device. The 2D potential distribution in the channel of the short-channel device has been obtained by solving the 2D Poisson's equation by using suitable boundary conditions. The effects of excess carrier generation due to the incident optical radiation in channel region have been included in the Poisson's equation to study the optical effects on the device. The potential function has been utilized to model the threshold voltage of the device under dark and illuminated conditions. The proposed model has been verified by comparing the theoretically predicted results with simulated data obtained by using the commercially available ATLAS TM 2D device simulator.
Optically gated MOSFET modeling
Proceedings of the International Conference and Workshop on Emerging Trends in Technology, 2010
In the recent decades, interest has been shown by the researcher towards the modeling of the optical effects on MOSFET with submicron channel length. It is mainly because device is expected to emerge as potential device to be integrated as MMIC, OEIC and ASIC for optical based system particularly optical communication. Present paper makes an attempt to investigate dependence of I-V characteristics and transconductance on optical illumination. Optical effects are mainly due to the lowering of surface potential barrier in presence of illumination called photon induced barrier lowering (PIBL). Investigation shows that drain current and the trans-conductance increases significantly in the presence of optical illumination. The device is expected to emerge for high speed application in optical system viz. photo-detector, optical switch, and imaging.
An improved model of ion-implanted GaAs OPFET
IEEE Transactions on Electron Devices, 1992
The paper presentes a seminumerical model of an ion-implanted GaAs OJtical-Eield-Effect-Transistor (OPFET). The objective of the present work is to overcome the limitations of the existing model [I] without changing the basic approach. Analytical expressions obtained using one-dimensional Poisson's equation have been solved numerically to obtain the I-V characteristics of the device in dark and illuminated conditions. It is seen that the saturation drain current of the device changes significantly in the illuminated condition. The existing model of the device [l] has been improved in the present analysis by considering the effects of photovoltage generated across the metal-semiconductor junction and optical modulation of depletion edge depths in the illuminated condition. Unlike in the previous model [l] it has been concluded that for a high gate bias resistance the optical radiation controls the saturation drain current by changing the channel conductance rather than its conductivity.
Threshold Voltage Model for Ion Implanted Short Gate Length GaAs MESFETs under Dark
In the present work, an attempt has been made to analytically model the threshold voltage of short-channel optically controlled GaAs MESFETs with a vertical Gaussian profile. The two-dimensional (2D) Poisson's equation has been solved with suitable boundary conditions using superposition method to obtain an optical radiation dependent threshold voltage expression. The credibility of the model is established by comparison of the calculated threshold voltage with the numerical simulation data obtained by ATLAS TM device simulator.
An analytical 2D model to predict the potential distribution of short-channel ionimplanted GaAs MESFETs has been presented. The 2D potential distribution in the channel of the short-channel device has been obtained by solving the 2D Poisson's equation in conjunction with suitable boundary conditions using superposition method. The remarkable feature of the proposed model is that the implanted doping profile has been treated in completely analytical manner. A double-integrable Gaussian-like function has been assumed as the doping distribution profile in the vertical direction of the channel. The effects of excess carrier generation due to the incident optical radiation in channel region have been included in the Poisson's equation to study the optical effects on the device. The photovoltage developed across the gate metal has also been modeled. The proposed model has been verified by comparing the theoretically predicted results with simulated data obtained by using the commercially available ATLAS TM 2D device simulator.
International Journal of Engineering Research and Technology (IJERT), 2012
https://www.ijert.org/matlab-based-analytical-model-for-short-channel-gaas-mesfet-for-the-distribution-of-potential-and-threshold-voltage-under-dark-and-illuminated-conditions https://www.ijert.org/research/matlab-based-analytical-model-for-short-channel-gaas-mesfet-for-the-distribution-of-potential-and-threshold-voltage-under-dark-and-illuminated-conditions-IJERTV1IS7488.pdf Optoelectronic is one of the thrust areas for the recent research activity. One of the key components of the optoelectronic family is photo detector to be widely used in broadband communication, optical computing, optical transformer, optical control etc. Present paper includes the investigation carried on the basis of the 2 D (two dimensional) mathematical modeling for the potential distribution and threshold voltage of short-channel ion-implanted GaAs-MESFET operated in the sub threshold. Device is assumed to have the double-integrable Gaussian like function as the doping distribution profile in the vertical direction of the channel .The Schottky gate has been assumed to be semi-transparent through which optical radiation is coupled in to the device. Investigation shows the 2D potential distribution in the channel of the short channel device by using 2D Poisson's equation and suitable boundary conditions. It also shows that the effect of excess carrier generation due to the incident optical radiation in the channel, the potential function has been utilized to model the threshold voltage of the device under dark and illuminated conditions. Result's that theoretical predicted for device and using MATLAB.
Modeling of Photodependent Capacitance for Short Gate length Ion implanted GaAs MESFETs
This paper presents an analytical model for C-V characteristics of short gate-length GaAs MESFET under illuminated condition. The non-analytic Gaussian doping profile commonly considered for the channel doping of an ion-implanted GaAs MESFET has been replaced by an analytic Gaussian-like function for the simplicity of the present model. When the computed results of the proposed model are compared with numerical simulation data obtained by ATLAS TM device simulator, an encouraging correspondence between the two lends credibility to our model.
Time dependent analysis of an ion-implanted GaAs OPFET
IEEE Transactions on Electron Devices, 1994
A time-dependent analysis of the electrical characteristics of an ion implanted GaAs optical field effect transistor (OPFET) has been carried out. Both the cases of light turning on and off at a reference time t = 0 have been considered. The photovoltaic effect across the Schottky junction and the depletion width modulation in the active layer have been taken into account. The threshold voltage, channel charge, channel conductance, drain-source current, transconductance, and gatesource capacitance of the device under light turning on and off conditions have been evaluated. When light is turned on, all the parameters increase with time before reaching the steady-state value and when light is turned off, these parameters decrease with time and reach their respective values corresponding to dark condition. The time under on condition is less than that under off condition.
International Journal of Engineering Research and Technology (IJERT), 2013
https://www.ijert.org/modelling-for-formation-of-sourcedrain-region-by-ion-implantation-and-diffusion-process-for-mosfet-device https://www.ijert.org/research/modelling-for-formation-of-sourcedrain-region-by-ion-implantation-and-diffusion-process-for-mosfet-device-IJERTV2IS80676.pdf The main aim of this paper is to optimize the parameters needed to fabricate the MOSFET device using Active simulation process (simulator: MT3.00). The simulator consists of three programs hidden under one shell called MicroTech TM. It is well known that to fabricate MOSFET device, one of the most important steps is the formation of Source/Drain region. The ion implantation or diffusion process with different impurities is used for formation of source/drain region of MOSFET device. A comparative study is reported here between Arsenic and Boron concentration profile with ion implantation and diffusion process using the MicroTech simulator. To fabricate the n-channel MOSFET device, it is observed that in case of 70KeV ion energy doping concentration is maximum near to the surface, as observed from boron concentration profile using ion implantation process, which is also observed in case of p-channel MOSFET. To fabricate source/drain region of MOSFET device using diffusion process, it is observed that in case of 500⁰C doping concentration is maximum near to the surface for both kinds of dopants. Ion implantation process is more effective compared to the diffusion process as observed from the doping concentration profile in case of all dopants.