电子衍射条件对Si(111)外延时反射式高能电子衍射强度振荡的影响

THE EFFECT OF ELECTRON DIFFRACTION CONDITIONS ON RHEED INTENSITY OSCILLATIONS DURING Si(111) MBE

本文研究了不同电子衍射条件对Si(111)外延时的反射式高能电子衍射(RHEED)强度振荡的影响,在保持生长条件不变的情况下,沿[112]方位观测时,不同入射角下其强度振荡的相位和初始瞬态响应变化很大,甚至会发生180°相位变化,而在[011]方位观测时,其相位的变化不明显,结合Si(111)面的RHEED强度摇摆曲线测量结果,表明这种与电子衍射条件有关的振荡特性变化,实际上反映了由电子多重散射机理引起的RHEED强度振荡两种情形,对RHEED强度的初始瞬态响应机理也作了探讨。

The Reflection High Energy Electron Diffraction (RHEED) intensity oscillations under different angles of incidence and azimuths during Si(111) molecular beam epitaxy have been studied. The phase of intensity oscillation and initial transient response change dramatically with the angles of incidencl if the observation is carried out along [112] azimuthal direction, but vary little when observed along [011] azimuth. From the measurement results of RHEED specular beam rocking curve, we believe that, the characteristics of RHEED intensity oscillation as a function of electron diffraction condition, indicate the existence of two different seattering processes: coherently elastic diffraction beam oscillation and inelastic or diffuse scattering beam oscillation. This can be explained only by the electron multiple scattering mechanism. The origin of initial transient is also discussed.