Influence of HALO and drain-extension doping gradients on transistor performance

For achieving a physical gate length lower than 50 nm and keeping at the same time good transistor performance, a careful design of drain-extension and channel doping profiles is required. For this we investigate the influence of drain-extension and HALO doping gradients at the drain-extension channel junction (DECJ). It is found that the influence of the drain extension doping gradient on the threshold voltage roll-off behavior is small for steep profiles when keeping saturation current and overlap capacitance constant. On the other hand, the shape of the HALO profile influences the threshold voltage roll-off characteristics and allows to adjust the roll-off behavior without degrading the saturation current dramatically. The effect of process parameters like HALO implantation angle and energy on the transistor performance is studied.