Si(011)16×2 gas-source molecular beam epitaxy: Growth kinetics

The growth rates R_Si of Si layers deposited on Si(011)"16×2" by gas-source molecular beam epitaxy from Si₂H₆ were determined as a function of temperature T_s (400-975 °C) and Si₂H₆ flux J_Si2H6(5.0×10¹⁵-9.0×10¹⁶cm ^-2s^-1). R_Si ranges from 0.0015 μmh^-1 at T_s=400°C to 0.415 μm h^-1 at T_s=975 °C with J_Si2H6=2.2×10¹⁶cm^-2s^-1. In the surface-reaction-limited regime at T_s <725 °C, R_Si initially exhibits an exponential decrease with 1/T_s, then decreases at a slower rate at T_s≤550°C as an additional deposition pathway becomes operative. In the impingement-flux-limited regime. 725≤T_s≤900°C, R_Si is independent of T_s but increases linearly with J_Si2H6. At T_s>900°C, R_Si(T_s) increases with T_s due to surface roughening. Overall, R^·_Si(J_Si2H6,T_s) is well described at T_s≤900°C by a kinetic model incorporating two competing film growth mechanisms: (1) dissociative chemisorption of Si₂H₆ onto dangling bonds followed by fast surface dissociation steps and second-order H₂ desorption from the surface monohydride phase; and (2) Si₂H₆ insertion into Si-H surface bonds followed by second-order desorption of SiH₄.