Formation of Pd Nanodots Induced by Remote Hydrogen Plasma and Its Application to Floating Gate MOS Memories

Abstract

We have studied the formation of Pd-nanodots on SiO2 from ultrathin Pd films being exposed to remote hydrogen plasma at room temperature, in which parameters such as the gas pressure and input power to generate H2 plasma and the Pd film thickness were selected to get some insights into surface migration of Pd atoms induced with atomic hydrogen irradiation and resultant agglomeration with cohesive action. The areal dot density was controlled in the range from ∼3.4 to ∼ 6.5×1011 cm-2 while the dot size distribution was changed from ∼7 to ∼1.5 in average dot height with ∼40% variation in full-width at half maximum. We also fabricated MOS capacitors with a Pd-nanodots floating gate and confirmed the flat-band voltage shift in capacitance-voltage characteristic due to electron injection to and emission from the dots floating gate.