This disclosure enables high-productivity controlled fabrication of uniform porous semiconductor layers (made of single layer or multi-layer porous semiconductors such as porous silicon, comprising single porosity or multi-porosity layers). Some applications include fabrication of MEMS separation and sacrificial layers for die detachment and MEMS device fabrication, membrane formation and shallow trench isolation (STI) porous silicon (using porous silicon formation with an optimal porosity and its subsequent oxidation). Further, this disclosure is applicable to the general fields of photovoltaics, MEMS, including sensors and actuators, stand-alone, or integrated with integrated semiconductor microelectronics, semiconductor microelectronics chips and optoelectronics.