Self-Consistent Quasi Static CV Characterization of In x Ga 1-x Sb Buried Channel n-MOSFET Muhammad Shaffatul Islam 1* , Md. Nur Kutubul Alam 1 and Md. Rafiqul Islam 1 Department of Electrical and Electronic Engineering Khulna University of Engineering & Technology Khulna-9203, Bangladesh *Corresponding author : mashru.islam@yahoo.com Abstract The quasi-static capacitance-voltage (CV) characteristics of buried channel n-InGaSb MOSFET is investigated using SILVACO’s ATLAS device simulation package. Self-consistent method is applied to solve the coupled one dimensional Schrödinger-Poisson equation taking into account of wave function penetration and strain effect. It is found that the CV profiles and threshold voltage are strongly depended on some important process parameters like oxide thickness, channel thickness, channel composition and temperature for buried channel InGaSb n-MOSFET. INTRODUCTION Silicon is the most widely used and established semiconductors, which dominates the electronic industry for the last 25 years. The mainstream digital electronics fabricated by CMOS approach is a method for minimizing standby power [1]. When the dimension of the silicon-based MOSFETs is scaling down to their ultimate limits, many adverse effects arise that degrade the device performance. Parasitic resistance as well as the scattering at the oxide-silicon interface results the degradation of mobility that lowers the device speed. As a result, it is impossible to operate it in the ballistic limit(corresponding to channel length approaching zero) [1]. For the limitations of Si and the quest for ever better performance as envisioned by the ITRS (International Technology Roadmap for Semiconductors) has had researchers looking into the possibilities of CMOS circuits that utilize III-V materials either alone or in hybrid form with germanium [2]. III-V materials have emerged as a promising candidate for channel material of MOSFETs. Due to excellent transport and electronic properties, III-V materials can be used in the channel of MOSFETs for future logic applications, where high performance and low power are required [3]. It is well known that InSb shows highest electron mobility and using InSb the low power and high speed quantum well devices were obtained in previous studies [4,5]. Recently, InGaSb-based surface channel MOSFET has been reported in [6] where mobility of the device was experimentally demonstrated. Self-consistent capacitance-voltage (CV) characterization including direct tunneling gate leakage current was reported for surface channel n-MOSFET in [7]. It is well established that the buried channel MOSFET shows better performance than surface channel MOSFET. To best of our knowledge there is no work Fig 1. Proposed In x Ga 1-x Sb buried channel n-MOSFET structure. on CV characterization of buried channel MOSFET. To understand the process parameters dependence of CV characteristics and threshold voltage of buried channel n-MOSFET, the present study is performed. PROPOSED DEVICE STRUCTURE The buried channel structure shown in Fig. 1 consists of Al gate contact and 10nm Al 2 O 3 gate dielectric. 7nm In x Ga 1-x Sb channel is buried below the 3nm Al x In 1-x Sb spacer layer which leads to isolate the channel from the direct contact of the oxide layer. 1μm Al x Ga 1-x Sb buffer layer is used on the top of the GaAs substrate to minimize the lattice mismatch between the substrate and the channel material. In this study, quasi static CV characteristics are investigated using SILVACO ATLAS device simulation package as a function of different process parameters. For the proposed structure, the self-consistent Schrodinger-Poisson equation is solved [8] including the wave function penetration and strain effects. Doping concentration of 10 17 cm -3 is used in both channel and buffer regions. To have a high quality spacer-channel interface, undoped spacer layer is used. RESULTS AND DISCUSSION In the present study, we have simulated gate CV characteristics of the proposed buried channel In x Ga 1-x Sb n-MOSFET as a function of different process parameters like oxide thickness, channel thickness, channel composition and temperature solving coupled one dimensional Schrödinger-Poisson equation using SILVACO’s ATLAS device simulation package. Al2O3 AlInSb InGaSb AlGaSb GaAs Substrate S D 94 978-1-4673-4842-3/13/$31.00 c 2013 IEEE