The Veeco Dopant Source is designed for efficient operation, rapid thermal response, and excellent flux uniformity. To achieve good uniformity with the relatively small charge used for dopant materials, a conical PBN crucible with a large taper angle is used to ensure excellent flux distribution across the entire substrate platen without beam shadowing or collimation.
The source operates efficiently at the relatively high evaporation temperatures required for most dopant materials, without excessive thermal load on the surrounding MBE growth chamber. While small dopant sources are heated with a single filament, the larger dopants feature a pair of concentric heater filaments operated in parallel to provide the most reliable and efficient source heating and responsiveness.
Due to the small size of the Dopant Sources for single-wafer MBE systems, this source may be combined on a single mounting flange with a secondary dopant source or gas inlet tube, thereby expanding the range of dopants available in a single source port. The gas inlet heated by the source filament, is intended for gases which do not require thermal pre-cracking, such as CBr4. The dual-dopant source has two 5cc source heads that are thermally and optically isolated from each other with independent shutters and is mounted on a single 4.5”/114mm flange.