TEMPERATURE-DEPENDENT AND RATE-DEPENDENT RHEED OSCILLATION STUDIES OFEPITAXIAL FE(001) ON CR(001)

Reflection high-energy electron diffraction (RHEED) intensity studies were performed during the growth of thin Fe layers on vicinal Cr(001)/ Nb(001)/Al2O3(1 (1) over bar 02) substrates. The results are compared with those of recent molecular-beam epitaxy (MBE) growth models. Gener al agreement is found as concerns the linear relationship between the logarithm of the number of RHEED oscillations and the inverse growth t emperature. In agreement with theory the RHEED oscillation damping tim e is found to depend algebraically on the growth rate. However, contra ry to expectations, the RHEED oscillations vanish faster at higher gro wth temperatures and lower growth rates. This behavior can be explaine d by a change in the growth mode from layer-by-layer to step flow. Num erical simulations in which step bunch melting during the Fe growth on the Cr buffer is assumed reproduce well the present experimental resu lts. [S0163-1829(98)02708-8].