Physics Based Simulation and Calibration of GaN/AlGaN/GaN HEMT Device
This study is intended to establish physics-based TCAD (Technology Computer Aided Design) simulation methodology for normally ON GaN/AlGaN/GaN HEMT (High Electron Mobility Transistor) device performance verification. Calibration work is based on literature review and GaN wafer experimental data. Not only fixed charge and donor like traps concentration but also barrier height, tunneling coefficient and energy level for traps also plays vital role in the calibration process as discussed in the paper
Investigations of Low Dynamic Ron on GaN/AlGaN/GaN HEMT by Field Plate Using Physical Device Simulations
This paper examines the effects of field plate structure with gallium nitrite cap contact scheme and inter layer dielectric (ILD) as nitride on the performance of GaN/AlGaN/GaN High electron mobility transistor (HEMT). We have exhibited the main results of the field plate are to regulate the field distribution in the channel and to decrease its peak value on the drain side of the gate edge. The advantage is an increase of the breakdown voltage. These Synopsys Technology Computer Aided Design (TCAD) simulated results clearly show that besides field plate design dielectric material thickness also plays a vital role to obtain low dynamic Ron ratio.
FULLY ION-IMPLANTED 1200V LDMOS WITH LINEAR P-TOP TECHNOLOGY
In this paper, fully ion implanted 1200V UHV LDMOS with a linear P-top device has been proposed. The epitaxy layer is replaced by a triple phosphorus ion implantation. The results achieve an on-resistance of lower than 370 mΩcm2 while maintaining a breakdown voltage of over 1200 volts. The key feature of this device is the linear P-top based on an optimized drift doping profile according to resurf principle . It also shows the reduction of the peak electric field from 2.68e5v/cm to 2.31e5V/cm with the comparison to epitaxy layer . This device can eliminate Vth photo masking and ion implantation processes.
An Innovative TCAD Simulated UHV-PLDMOS Device with Improved HTRB Performance.
This study proposed an innovative TCAD simulated ultra-high voltage p-type laterally diffused metal oxide semiconductor device structure with metal II field plate optimization, which could improve high-temperature reverse-bias (HTRB) performance. By optimizing the metal II field plate position, the exposed area could be minimized, and furthermore, after using the passivation layer of oxide-(a-Si: H)-oxide-(a-Si: H)-nitride after stress, the hole trap concentration was much lower than that in the silicon nitride and silicon dioxide passivation region because of the low mobility of (a-Si: H), which was 1 cm2v-1s-1. The new passivation layer maintained the original p-drift reduced surface field (RESURF) doping profile and exhibited less degradation in terms of losing positive ions from the p RESURF channel crossing oxide and entering the traps. The five layers exhibited fewer traps; therefore, the degradation was improved. The reliability of the device could be increased by changing the doping concentration of the drift region according to the RESURF principle. In addition, this study compared two passivation layers of (oxide–silicon nitride) and five passivation layers of oxide- (a-Si: H)-oxide- (a-Si: H)-nitride.
COMPARISON OF SIMULATION TOOLS FOR BCD INTEGRATION
This paper investigates on how Sprocess from Sentaurus compare against TSUPREM-4 simulation doping profile and fit Silicon data and/or SIMS (Secondary Ion Mass Spectrometry) profile. Currently, TSUPREM-4 has been using for process simulation for device design. But for BCD(Bipolar CMOS-DMOS) integration there are many new SOA (Safe Operating Area) features such as HCI (Hot Carrier Injection), HTRB, UIS etc., are required for reliability design which are available in Sprocess. Sprocess have the updated models available for device simulation. In this study, we have investigated on some critical doping processes such as tilt implantation. P-top with the deep Nwell for LDMOS and low energy, low dose doping for short channel CMOS logic process. We have found both as-implant and post diffusion profiles are not similar due to the different algorithm and point defect maps post implantation. The effort has been made to calibrate profiles against both silicon data and SIMS profiles. We report the final results seem to indicate Sprocess requires Silicon calibration or SIMS profile comparison for these critical processes for future BCD process integration Work.
The new generation of hearing aid: Development the new opto-electromagnetic hearing aid and miniaturization
In the case of the conventional hearing aids, a microphone picks up acoustic energy before being transformed into an electrical signal and then amplified. A high frequency response is limited due to acoustic feedback, whereas small receivers tend to have a large distortion at low frequencies. An implantable middle ear hearing aid has been developed to overcome the problems of the conventional hearing aid. We tried to develop the photoelectric vibration transducer for hearing aid. The most important of all, no operation was needed. Besides, in order to optimize the photo-electromagnetic force and to predict the frequency characteristics, finite element analysis simulation was performed. The fabricated electromagnetic vibration transducer showed the possibility of applications an implantable middle ear hearing aid. Further work aimed at the in vivo experiment for the human implant by using of rapidly improved micromachining technology would be carried out.
Development the novel Bone Guided Cochlear Prosthesis for hearing impairment
Historical records describe the treatment of deafness among ancient and primitive tribes through the placement of minerals or plant extracts into the ear canal. Although medical interventions for conductive hearing impairment progressed significantly over the years, treatment for sensorineural deafness remained essentially no more effective than these early attempts until the last quarter of the twentieth century. It has only been in the past 20 years that physicians have been able to successfully treat profound sensorineura l hearing loss with cochlear implants (CIs). The stimulation of the acoustic nerve originates from a current flow between the electrodes. Current spread from a conventional electrode array is quite well-known from a couple of papers. However, the current CI technology still has many disadvantages including meningitis and loss of residual hearing. Therefore, our group will develop a novel bone conduction cochlear prosthesis for hearing impairment.
Development of a novel ultrasonic nozzle with micro-tip applies in the drug delivery device for inner ear therapy in diabetic rats and guinea pigs with acute hearing loss by noise exposure
There is increasing interest in the possibility of treating disorders of the inner ear by applying drugs directly to the cochlea. Clinically local applications of gentamicin to the round window membrane of the cochlea are gaining widespread acceptance as appropriate treatments for Meniere’s disease. There are also an increasing number reports related to the local application of glucocorticoids for sudden idiopathic sensorineural hearing loss, immune-associated hearing loss and tinnitus. There is also interest in the use of growth factors, antioxidants or apoptosis inhibitors, some of which have been successfully tested in preclinical studies. However, transtympanic injection of glococorticoids is not suitable for DM patients with high blood glucose level. Besides, painful sensation with transtympanic injection is another problem which could not be used in children. Therefore, we try to develop a new novel aerosol mediated device which can be applied in the delivery of glucorcorticoid or gentamicin to the middle ear space and diffuse to the inner ear. Monodisperse droplets are produced in ultrasonic atomization using a micro electro mechanical system (MEMS)-based 1-Fourier horn 0.5 MHz silicon nozzle. As medicine enters the 100μm x 100μm central channel of the nozzle, a curved thin liquid film is maintained at the nozzle tip that vibrates at the resonance frequency of 486.5 kHz, resulting in formation of standing capillary waves on the free film surface. Temporal instability of these standing capillary waves occurs as the tip vibration amplitude exceeds a threshold, and a spray of droplets (mist) is produced. The droplets measured by laser diffraction technique are 7.0 μm in diameter and could be easily delivered to the human middle ear space and diffuse to the inner ear through the round window membrane.
A new aerosol mediated device for inner ear therapy: from 3-dimensional model reconstruction to cochlear pharmacokinetics and in vitro experiment.
There is increasing interest in the possibility of treating disorders of the inner ear by applying drugs directly to the cochlea. Clinically local applications of gentamicin to the round window membrane of the cochlea are gaining widespread acceptance as appropriate treatments for Meniere’s disease. There are also an increasing number reports related to the local application of glucocorticoids for sudden idiopathic sensorineural hearing loss, immune-associated hearing loss, tinnitus. There is also interest in the use of growth factors, antioxidants or apoptosis inhibitors, some of which have been successfully tested in preclinical studies. However, transtympanic injection of glococorticoids is not suitable for DM patients with high blood glucose level. Besides, painful sensation with transtympanic injection is another problem which could not be used in children. Therefore, we try to develop a new aerosol mediated device which can be applied in the delivery of glucorcorticoid or gentamicin to the middle ear space and diffuse to the inner ear. Atomization (spray) is the breakup of a volume of liquid into drops, resulting in a dramatic increase in the surface area available for heat and mass transfer in solvent evaporation. Our groups developed an ultrasonic atomization system using MHz SAW devics. The advantages are large electromechanical coupling coefficient, a high acoustic velocity and a high potential for mass production of any resonator profile by microelectromechanical system (MEMS)-based fabrication technology. The droplets measured by laser diffraction technique are 5.0~10 μm in diameter and could be easily delivered to the human middle ear space and diffuse to the inner ear through the round window membrane.