Spectrally and Temporally Engineered Processing using Photoelectrochemistry

An apparatus for fabricating a specified structure in a semiconductor substrate having a surface, the apparatus comprising:

• a. a source of light;
• b. a modulator for modulating a duration of illumination of the semiconductor substrate
• c. a spectral filter for defining a spectral characteristic of light from the source that is incident upon the semiconductor substrate;
• d. a spatial light modulator for defining the spatial pattern of illumination incident on the semiconductor substrate;
• e. a container for maintaining an etch solution in contact with the surface of the semiconductor substrate;
• f. an electrode for maintaining a potential across the etch solution relative to the semiconductor substrate;
• and
• g. a processor for governing a temporal relationship between the duration of illumination and the potential across the interface between the semiconductor and etch solution.

A method for fabricating a photonic integrated circuit, the method comprising:

• a. growing a layered stack of semiconductor materials;
• b. creating an adiabatic taper between an active section and a passive section by performing one of displaying a gradient pattern of light intensity or displaying a sequence of images to slowly vary the etch height;
• and
• c. defining a photonic device in at least one of the active and passive sections using at least one of conventional photolithography, dry etching, deposition, and photoelectrochemical processing by illuminating with a pattern of light in such a manner as to cause etching, doping, or metallization.