Influence of irregular growth of monoatomic steps during Si/Si(001) epitaxy on generation of surface defects

We present results of STM investigation of surface of the Si epitaxial layers deposited on different Si(001) vicinal substrates at the step flow growth mode. We have observed two types of the growth defects looking like meandering or pits. The way of the defects formation does not depend on the direction of tilt of the Si(001) substrate. The formation of the defects is connected with particularities of the processes of the movement onto terraces and attachment to the step edge of Si ad-atoms during growth. We suppose that Ehrlich-Schwoebel and kink Ehrlich-Schwoebel effects drive irregular growth of the monoatomic steps during Si/Si(001) epitaxy. Process of the defect formation starts when the deep kink confined by two S a steps appears on the step edge. Next difference between growth rate of the S a and S b steps results in formation of the area with other morphology.