The invention relates to methods for manufacturing
semiconductor devices. Processes are disclosed for implementing suspended
single crystal silicon nano wires (NWs) using a combination of anisotropic and isotropic etches and spacer creation for sidewall protection. The core dimensions of the NWs are adjustable with the integration sequences: they can be triangular, rectangular, quasi-circular, or an alternative polygonal shape. Depending on the length of the NWs, going from the sub-micron to
millimeter range, the NWs may utilize support from anchors to the side, during certain
processing steps. By changing the lithographic dimensions of the anchors compared to the NWs, the anchors may be reduced or eliminated during
processing. The method covers, among other things, the integration of Gate-All-Around NW (GAA-NW) MOSFETs on a bulk
semiconductor. The GAA structure may consist of a
silicon core fabricated as specified in the invention, surrounded by any
usable gate dielectric, and finally by a gate material, such as polysilicon or
metal. The source and drain of the GAA-NW may be connected to the bulk
semiconductor to avoid
self heating of the device over a wide range of operating conditions. The GAA-NW
MOS capacitor can also be used for the integration of a Gate-All-Around
optical phase modulator (GAA modulator). The working principle for the
optical modulator is modulation of the
refractive index by
free carrier accumulation or inversion in a MOS capacitive structure, which changes the phase of the propagating light.