Passivation effects of phosphorus on 4H-SiC(0001) Si dangling bonds: A first-principles study

The effect of phosphorus passivation on 4H-SiC(0001) silicon (Si) dangling bonds is investigated using ab initio atomistic thermodynamic calculations. Phosphorus passivation commences with chemisorption of phosphorus atoms at high-symmetry coordinated sites. To determine the most stable structure during the passivation process of phosphorus, a surface phase diagram of phosphorus adsorption on SiC (0001) surface is constructed over a coverage range of 1/9-1 monolayer (ML). The calculated results indicate that the 1/3 ML configuration is most energetically favorable in a reasonable environment. At this coverage, the total electron density of states demonstrates that phosphorus may effectively reduce the interface state density near the conduction band by removing 4H-SiC (0001) Si dangling bonds. It provides an atomic level insight into how phosphorus is able to reduce the near interface traps.