Effect of Boron Dose and Post-thermal Budget on Electrical Properties of MOS-Capacitors with a W / WN x / poly ­ Si1 − xGex Gate Stack

Abstract

We investigated the effect of boron dosage and post-thermal budget on the electrical properties such as capacitance-voltage (C-V), gate leakage current-voltage and charge-to-breakdown of metal oxide semiconductor (CMOS) capacitors with gates stack. The C-V curve of the MOS-capacitors with the stack had a lower flatband voltage and showed less gate depletion effect (GDE), compared with that of the stack due to the decrease of gate electrode work function and the increase of dopant activation rate with the increase of Ge content, respectively. Although the curves of MOS-capacitors with gates stack exhibited similar behaviors regardless of Ge content, the beginning of conduction in the curves accelerated with the increase of Ge content due to the decrease of the gate electrode work function. The of gates stack was much higher than that of the gates stack due to the reduced boron penetration in the gate oxide. We also found that annealing temperatures between 800 and 850°C had no influence on the electrical properties of MOS capacitors with gates stack. © 2003 The Electrochemical Society. All rights reserved.