Impact of interface micro-roughness on low frequency noise in (110) and (100) pMOSFETs

In this paper we describe the evaluation of the dependence of low frequency noise upon the micro-roughness of the surface in pMOSFETs, based on (100) and (110) oriented silicon. For the (110) surface, because RCA cleaning makes the surface rough, we developed a 5 step room temperature cleaning process which does not use alkaline solution. As a result a drop of more than a decade in 1/f noise level was achieved. This low noise level is further reduced by using the process of microwave-excited high-density plasma oxidation of the gate oxide instead of thermal oxidation. This reduction is also observed for a (100) surface if treated in the same way, but the magnitude of the drop is less.