A MODIFIED BCF MODEL TO QUANTITATIVELY DESCRIBE THE (100)INP GROWTH-RATE IN CHEMICAL BEAM EPITAXY

The growth rate and the diffusion length are crucial parameters from t he viewpoint of both growth kinetics and applications, notably in the emerging field of selective area epitaxy. We have found that the verti cal (100) growth rate of InP grown by CBE depends not only on group II I Bur and temperature, but also on the substrate misorientation angle. It decreases by a few percent for lower misorientations and the effec t becomes more pronounced at higher temperatures. This is due to an in creased probability for desorption of the group III adatoms. To quanti tatively describe this growth rate dependence we developed a model bas ed on classical crystal growth theories for step flow (BCF) and 2D nuc leation. Using only two free parameters, we obtain an excellent fit to the experimental data. We find a value of E-d - E-s of 0.47 +/- 0.01 eV, corresponding to a diffusion length of 13 nm at 515 degrees C, and , for the first time, the energy barrier for the formation of a critic al 2D nucleus, Delta G, with values between 52 and 34 meV for growth rates from 0.3 to 0.6 mu m/h. (C) 1998 Elsevier Science B.V. All right s reserved.