~ Pergamon Renewable Energy, Vol. 14, Nos. 1-4, pp. 141-147, 1998 © 1998 Published by Elsevier Science Ltd. All rights reserved Printed in Great Britain Plh S0960-1481 (98) 00060-3 0960-1481/98 $19.00+0.00 Optimization of Arbitrarily Doped MINP + solar cell Performance MOHAMED ABDEL-GAWADEL-SAYED AND MOHAMEDABBASABDEL-RADY Department of Electrical&Electronic Eng. Faculty of Eng., University of Assiut,Egypt, Fa, r.(+20)088 332553 ABSTRACT. A comprehensive model of four layered MINP+ ( metal-tunnel insulator - NP ÷ sermconductor ) structure incorporating an inhomogeneous impurity doping profile is numerically simulated. The influence of built-in electric field m the device on its performance is investigated. The drift fields are the result of the nonuniformaly doped semiconductor. The dependence of the minority carrier lifetime and mobility on the doping density are taken into account. Solution curves for the complete set of transport , continuity and Poisson equations for the device as solar cell are obtained. Significant device parameters are identified and model calculations are carried out over a range covering most physically realizable values for these parameters. The I-V characteristics are calculated as a function of insulator thickness, metal workfunction, substrate doping density and sermconductor thickness with present semiconductor fabrication technology. © 1998 Published by Elsevier Science Ltd. All rights reserved. KEYWORDS Drift field; solar cell; MINP devices; Modeling of MINP solar cell INTRODUCTION The metal-thin film insulator (MIS) structure is currently receiving much attention in solar cell studies. Both theoretical and practical investigations indicate that this structure offers a means of overcoming the principle deficiency of Schottky barrier solar cell namely low open-circuit photovoltage (Shewchun et al., 1977, Stag et al., 1976, Salter et al., 1977, Olsen 1976 and E1- Sayed , 1980). The potential use of low grade silicon, the minimization of impurity diffusion at gram boundaries during low temperature processing and the apparent suitability for automated manufacturing make the device attractive for large-scale terrestrial use. A new cell design incorporating the advantages of the MIS structure and the NP junction is the hybrid MIS and NP junction structure MINP ( Green et a1.,1983 ). In this structure the MIS is used as a top contact for the NP junction rather than an ohmic contact. This MIS section of the structure act as a block for the substrate majority carrier and at the same time it collect the photo-generated carriers and thereby giving a better performance. In the p-type base region of these devices the electron in the conduction band generated by the longer wavelength photons farther from the 141