First-Principles Calculation on Initial Stage of Oxidation of Si (110)‎-(1 × 1)‎ Surface

Abstract EN

The initial stage of oxidation of an Si (110)-(1 × 1) surface was analyzed by using the first-principles calculation.

Two calculation cells with different surface areas were prepared.

In these cells, O atoms were located at the Si–Si bonds in the first layer (A-bonds) and at the Si–Si bonds between the first and second layers (B-bonds).

We found that (i) the most stable site of one O atom was the A-bond, and (ii) an O (A-bond) –Si–O (A-bond) was the most stable for two O atoms with a coverage ratio of Rox=0.06 while an O (A-bond) –Si–O (B-bond) was the most stable for Rox=0.10.

The stability of O (A-bond) –Si–Si–O (A-bond) was less than the structures obtained in (ii).

The other calculations showed that the unoxidized A-bonds should be left when a coverage ratio of Rox is close to 1.

These simulations suggest that the O atoms will form clusters in the initial stage of oxidation, and the preferential oxidation will change from the A-bonds to the B-bonds up to the formation of 1 monolayer (ML) oxide.

The results obtained here support the reported experimental results.