EXACT OBSERVATION OF OXYGEN RADICALS BY VOLTAGE LOCKED LOOP METHOD FOR THE APPLICATION TO MOLECULAR-BEAM EPITAXIAL-GROWTH

The exact observation of oxygen radicals with molecular beam epitaxy ( MBE) is an important technology for a approach of growth conditions on stoichiometry and perfection on the atomic scale in oxide. The oxidiz ation method using radical sources of two types, and the determination and control of the number of activated oxygen utilizing voltage-locke d-loop (VLL) method are described. Coil type is more suitable for oxyg en radical source than electrode type. The relationship between the fl ux of oxygen radical and the rf power or oxygen partial pressure have been estimated. The flux of radicals increases as the rf power increas es, and indicates to the frequency change having the the value of abou t 2X10(14) atoms . cm(-2) . s(-1) when the oxygen now rate of 2.0 seem and rf power 150 W. Real-time control of flux using VLL method can be achieved successfully.