Surface roughness in silicon carbide technology

In this experiment the effect of selected process conditions on the roughness of silicon carbide surfaces was investigated. Both wet and dry surface conditioning steps were implemented to alter surface roughness of bare and epitaxial 4H SiC. It was determined that aggressive wet cleaning procedures increase surface roughness while the same process using dilute chemistries reduces surface roughness. Also, a remote plasma H₂N₂ exposure results in the reduction of surface roughness. Surface roughness was found to have a limited impact on the characteristics of SiC Schottky diodes. On the other hand a dependence of electrical integrity of gate oxides on SiC surface roughness was observed. Overall, SiC surfaces have been shown to display sensitivity to the chemical cleaning environment at least as pronounced as silicon.