Abstract: This invention provides methods for fabricating substantially continuous layers of a group III nitride semiconductor material having low defect densities and optionally having a selected crystal polarity. The methods include epitaxial growth nucleating and/or seeding on the upper portions of a plurality of pillars/islands of a group III nitride material that are irregularly arranged on a template structure. The upper portions of the islands have low defect densities and optionally have a selected crystal polarity. The invention also includes template structures having a substantially continuous layer of a masking material through which emerge upper portions of the pillars/islands. The invention also includes such template structures. The invention can be applied to a wide range of semiconductor materials, both elemental semiconductors, e.g., combinations of Si (silicon) with strained Si (sSi) and/or Ge (germanium), and compound semiconductors, e.g.

Abstract: A method and system for reliably reducing the formation of particles upon wafers or substrates during wafer processes is disclosed. The method and system reduces residue contamination of a substrate material during wafer processes by pre-filling a pressure chamber to a first pressure P1 with a purified pre-fill prior to filling the pressure chamber with a primary bulk source at a second pressure P2. By pre-filling a chamber with purified pre-fill source at the first pressure P1 which is substantially equal to the bulk source pressure P2, the contaminants found in the bulk CO2 remain within the bulk CO2. Thus, this method and system reduces precipitation of contaminates caused by the depressurization of the bulk source during wafer processes and thereby reduces corresponding substrate material contamination.