IEEE TRANSACTIONS ONNANOTECHNOLOGY, Volume 18, 2019 925 Extraction of Trench Capacitance and Reverse Recovery Time of InGaAs Self-Switching Diode Sahil Garg, Bipan Kaushal, Sanjeev Kumar, Shahrir Rizal Kasjoo , Santanu Mahapatra , and Arun K. Singh Abstract—In this paper, we have presented the transient analysis of an InGaAs based novel nano diode called self-switching device utilizing Silvaco TCAD simulator. The device exhibits current- voltage (I-V) characteristics analogous to a conventional diode without requiring any p-n junction. The cut-in voltage and the output current of the device can be tuned by varying channel width and length, respectively. The charging/discharging time (RC time constants) have been extracted from the I-V characteristics of the device demonstrating almost very small reverse recovery time of the order of 10 -9 s, which significantly affects the device on-off switching. Furthermore, results are validated by implementing the conformal mapping technique to extract device capacitance, which in turn predicts device charging and discharging, and hence, reverse recovery time to enable high frequency operation. Addi- tionally, it is demonstrated that small reverse recovery time enables SSDs to rectify the input signal without requiring additional filter circuitry. Index Terms—Reverse recovery, Self-switching device (SSD), Storage effect, Switching, Time constant. I. INTRODUCTION R EVERSE recovery time of barrier devices propose a major problem as they limit the switching rate. The conventional pn diodes have reverse recovery time of the order of 10 -7 s which makes them suitable for rectification applications with frequencies less than 1 MHz [1]. To overcome this problem, fast recovery diodes [2], [3] and Schottky barrier diodes (SBD’s) [4]–[6] were designed and developed demonstrating recovery time of the order of 10 -9 s. In case of a pn diode, steady state density of minority carriers are stored in depletion re- gion and semiconductor layers during the forward bias. These stored minority carriers need to be removed when the voltage Manuscript received February 27, 2019; revised July 10, 2019; accepted August 28, 2019. Date of current version September 13, 2019. This work was supported by Science and Engineering Research Board, Department of Science and Technology, Government of India under Grant EEQ/2018/000821. The review of this paper was arranged by NMDC2018 Guest Editors. (Corresponding author: Arun K. Singh.) S. Garg, B. Kaushal, and A. K. Singh are with the Department of Electronics and Communication Engineering, Punjab Engineering College (Deemed to be University), Chandigarh 160012, India (e-mail: sahilgarg343@gmail.com; bipan_pec@yahoo.com; arun@pec.ac.in). S. Kumar is with the Department of Applied Sciences, Punjab Engineering College, Chandigarh 160012, India (e-mail: sanjeev04101977@gmail.com). S. R. Kasjoo is with the School of Microelectronic Engineering, Uni- versity Malaysia Perlis, Kangar 01000, Malaysia (e-mail: shahrirrizal@ unimap.edu.my). S. Mahapatra is with the Department of Electronic Systems Engineering, Indian Institute of Science Bangalore, Bangalore 560012, India (e-mail: santanu@iisc.ac.in). Digital Object Identifier 10.1109/TNANO.2019.2939199 polarity is reversed. It results in a large reverse current to remove these injected minority carriers so as to achieve blocking capacity again, hence, large reverse recovery time. Schottky barrier diodes do not showcase this minority carrier storage effect and therefore, have a negligible reverse recovery time. However, the above stated diodes have a barrier in some form or the other which limits their switching performance upto GHz frequencies. Recent developments in field of Terahertz (THz) propose different types of unipolar devices which are free from any doped junction and/or potential barrier such as ballistic rectifier [7]–[9], three terminal junction (TTJ) [10], [11] and self-switching diode (SSD) [12]. SSD was first conceptualized and realized by Song et al. in 2003 utilizing two L-shaped trenches in In 0.7 Ga 0.3 As het- erostructures [13]. The device working resembles to a diode, however, does not require any doping junctions and/or Schottky barrier to produce non-linear I-V characteristics. The planar architecture of the device, i.e., the electrical contacts are on the same plane as of device, reduces the parasitic effects en- abling high frequency operation. SSDs have been studied and fabricated from wide variety of materials ranging from Silicon- on-Insulator [18] to two-dimensional electron gases (2DEGs) [30] to novel materials like graphene [15] and molybdenum disulphide (MoS 2 ) [19]. The device stated in this paper can be easily fabricated using InGaAs/InAlAs heterostructure with InP as substrate. The L shaped trenches can be etched using single step nanolithography. The high frequency operation in THz range suggests that SSDs can be employed for variety of applications including communication and imaging (secu- rity/medical) [14], [21]. The theoretical studies using Monte- Carlo simulations have demonstrated that SSD can also be used as microwave/terahertz emitters [22]. At such high frequency operation, the evaluation of charging and discharging time and hence, reverse recovery time of rectifier becomes important as it significantly affects the maximum cut off frequency of device operation. Despite previous experimental and theoretical studies of SSDs at improving performance, a detailed analysis of current–voltage characteristics (I-V) predicting charging/ discharging time con- stants and hence reverse recovery time of SSD are still very limited. Hence, we have performed a systematic transient anal- ysis of In 0.7 Ga 0.3 As SSD utilizing Silvaco TCAD to predict the device charging and discharging effects on device performance. The voltage pulses of different amplitudes and rise/fall time are applied. The corresponding output current response is evaluated to estimate the reverse recovery time of the order of 10 -9 s. The 1536-125X © 2019 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.