Exact observation of oxygen radicals by voltage locked loop method for the application to molecular beam epitaxial growth

The exacl observation of oxygen radicals with molecular beam epilaxy (MBE) is an important technology for a approach of growth conditions on stoichiomctry and perfection on the atomic scale in oxide. The oxidiJ.ation method using radical sources of two types, and the determination and control of the number of activated oxygen utilizing voltagc-Iockcd-loop (VLL) method are described. Coil type is more suitable for oxygen radical source than electrode type. The relationship between the flux of oxygen radical and the rf power or oxygen partial pressure have been estimated. The flux of radicals increases as iherf power increases, and indicates to the frequency change having the the value of about 2X1014 atoms cm^-2 s^-1 when the oxygen flow rate of 2.0 seem and rf power 150 W. Real-lime control of flux using VLL method can be achieved successfully.