Defect structure relaxation process in the Si–SiO system

The Si–SiO2system with a SiO2film prepared by high-temperature oxidation can be in a nonequilibrium state and a defect structure relaxation process is possible in this system. The paper presents the results of the electron spin resonance ESR.and MOS capacitance technique studies of the defect structure relaxation process in the Si–SiO2 system. It has been found that after sample preparation, the intensity of the ESR signal, connected with vacancy-type defects, increases; and the intensity of the ESR signal connected with nonsaturated Si[SiP bonds at the Si–SiO2interface Pbcentres.decreases with different time constants, indicative of different mechanisms of the defect structure relaxation process. At a longer storage time, nonmonotonous changes in the ESR signal intensity, the charge in the SiO2 films and the density of surface states have been observed. The nonmonotonous change in the ESR signal and the charge in SiO2 can be explained on the basis of the charge carrier electrons and holes.transfer from Si to SiO2 on the excited and ground state of the defects, respectively, and on the basis of their subsequent recombination. The defect structure relaxation process can be accelerated and the reliability of the manufactured devices improved by an appropriate choice of the oxidation conditions oxide thickness, cooling rate.. q2000 Elsevier Science B.V. All rights reserved.