Abstract
Thermal etch pits formed on (100) and (111) silicon surfaces heated in the temperature ranges 750°850°C in the vacuum chamber evacuated by the degraded ion pump system have been studied. The surface morphology was observed by scanning electron microscopy (SEM) and the residual gas analysis was performed by quadrupole mass spectroscopy (QMS). The etch patterns were triangular on the (111) and rectangular on the (100) surface. The pits appear to be due to the preferential etching of {111} plane. From the experimental results by QMS analysis, it is considered that the etching reaction is caused by residual H2O in the vacuum chamber.
