| 摘要 |
Methods and Systems producing flattening layers associated with nitrogen-containing quantum wells and to prevent 3-D growth of nitrogen containing layers using high As fluxes. MEE (Migration Enhanced Epitaxy) is used to flatten layers and enhance smoothness of quantum wells interfaces and to achieve narrowing of the spectrum of light emitted from nitrogen containing quantum wells. MEE is performed by alternately depositing single atomic layers of group III and V before, and/or after, and/or in-between quantum wells. Where GaAs is used, the process can be accomplished by alternately opening and closing Ga and As shutters in an MBE system, while preventing both from being open at the same time. Where nitrogen is used, the system incorporates a mechanical means of preventing nitrogen from entering the MBE processing chamber, such as a gate valve. The gate valve allows the nitrogen source to be completely cut-off from the chamber during non-nitrogen processing steps to achieve the flattening layers described herein. In at least nitrogen containing layers, 3-dimensional growth is also reduced by using high arsenic fluxes, and by using substantially As4 as the main constituent of the arsenic flux. |
