Band Engineered (Heterostructure) IMOS Device
Subject Areas : electrical and computer engineeringH. Godazgar 1 , محمدكاظم مروج فرشي 2 , مرتضی فتحی پور 3
1 - Tarbiat Modares University
2 -
3 - University of Tehran
Keywords: IMOS band to band tunneling breakdown voltage impact ionization ON/OFF current ratio,
Abstract :
A novel model for impact ionization metal-semiconductor (IMOS) device with an engineered bandstructure (heterostructure) has been proposed and simulated. The IMOS intrinsic, wherein the carrier generation is mainly due to impact ionization, controls the band to band tunneling. In the proposed model, it is assumed the intrinsic region to be SixGe1−x (0.5≤x≤1) whose bandgap varies linearly from that of Si at the source edge to that of Si0.5Ge0.5 at the gate edge. Maximum gap difference of ΔEG=ΔEC=0.32 eV appears at the source /intrinsic region interface. As a consequence, the probability of band to band tunneling and hence the device dark current is reduced. The numerical result shows that the breakdown voltage and the dark current for the proposed heterostructure IMOS are respectively ~0.3 V and four times smaller than those of the homojunction Si0.5Ge0.5-IMOS, with the same dimensions.
[1] F. Mayer, C. Le Royer, G. Le Carval, L. Clavelier, and S. Deleonibus, "Experimental and TCAD investigation of the two components of the impact ionization MOSFET (IMOS) switching," IEEE Electron Dev. Lett., vol. 28, no. 7, pp. 619-621, Jul. 2007.
[2] K. Gopalakrishnan, P. B. Griffin, and J. D. Plummer, "I-MOS: a novel semiconductor device with a subthreshold slope lower than kT/q," in Proc. Int. Electron Devices Meeting, IEDM'02, pp. 289-292, 8-11 Dec. 2002.
[3] K. Gopalakrishnan, P. B. Griffin, and J. D. Plummer, "Impact ionization MOS (I-MOS)-part i: device and circuit simulations," IEEE Trans. Electron Devices, vol. 52, no. 1, pp. 69-76, Jan. 2005.
[4] W. Y. Choi, Impact-Ionization Metal-Oxide-Semiconductor (I-MOS) Devices Using Avalanche Breakdown Mechanism, Ph.D. Dissertation, College of Eng, Seoul National Univ., 2006.
[5] E. H. Toh, G. H. Wang, L. Chan, G. Samudra, and Y. C. Yeo, "A double-spacer I-MOS transistor with shallow source junction and lightly doped drain for reduced operating voltage and enhanced device performance," IEEE Electron Device Lett., vol. 29, no. 2, pp. 189-191, Feb. 2008.
[6] E. H. Toh, G. H. Wang, L. Chan, G. Q. Lo, G. Samudra, and Y. C. Yeo, "I-MOS transistor with an elevated silicon-germanium impact-ionization region for bandgap engineering," IEEE Electron Device Lett., vol. 27, no. 12, pp. 975-977, Dec. 2006.
[7] U. Abelein, M. Born, K. K. Bhuwalka, M. Schindler, M. Schmidt, T. Sulima, and I. Eisele, "A novel vertical impact ionization MOSFET (I-MOS) concept," in Proc. 5th Int. Conf. Microelectronics. pp. 121-123, Belgrade, Serbia and Montenegro, 14-17 May 2006.
[8] E. H. Toh, et al., "A novel CMOS compatible L-shaped impact-ionization MOS (LI-MOS) transistor," in Proc. Int. Electron Devices Meeting, IEDM'05, pp. 951-954, 5-5 Dec. 2005.
[9] F. A. Hassani, M. Fathipour, and M. Mehran, "A comparison study between double and single gate p-IMOS," AFRICON, Windhoek, 7 pp., 26-28 Sept. 2007.
[10] D. Sarkar, N. Singh, and K. Banerjee, "A novel enhanced electric-field impact-ionization MOS transistor," IEEE Electron Device Lett., vol. 31, no. 11, pp. 1175-1177, Nov. 2010.
[11] H. Nematian, M. Fathipour, and M. Nayeri, "A novel impact ionization MOS (I-MOS) structure using a silicon-germanium/silicon heterostructure channel," in Proc. Int. Conf. on Microelectronics, pp. 228-231, 14-17 Dec. 2008.
[12] W. Y. Choi, J. Y. Song, J. D. Lee, Y. J. Park, and B. G. Park, "A novel biasing scheme for I-MOS (impact-ionization MOS) devices," IEEE Trans. Nanotechnology, vol. 4, no. 3, pp. 322-325, May 2005.
[13] F. Mayer, C. L. Royer, G. L. Carval, L. Clavelier, and S. Deleonibus, "Static and dynamic TCAD analysis of IMOS performance: from the single device to the circuit," IEEE Trans. Electron Devices, vol. 53, no. 8, pp. 1852-1857, Aug. 2006.
[14] K. Gopalakrishnan, R. Woo, C. Jungemann, P. B. Griffin, and J. D. Plummer, "Impact ionization MOS (I-MOS)-part ii: experimental results," IEEE Trans. Electron Devices, vol. 52, no. 1, pp. 77-84, Jan. 2005.
