Porous Silicon Etching

Complete wet etching system for porous silicon formation

Double cell HF tank for porous silicon etching with electrolytical backside contact

Single cell HF-bath for porous silicon formation

Flexible programmable power supply with control software for time-based current profiles


Porous silicon (PS) has gained wide-spread attention over the last decade for its interesting material properties, including nanometer features and extremely high specific surface area. Applications are, amongst others, humidity sensors, particle filters, optical elements and biochemical matrices. Microporous silicon is fabricated by etching silicon in HF-based solutions under applied voltage. Most fabrication processes for macroporous silicon need illumination in addition, an issue also addressed by AMMTs tools for PS formation.

AMMT’s line of PS equipment consists of:

  • The MPSB system, a double cell tank which holds the HF-based etchant and which is equipped with platinum electrodes
  • One or more wafer holders supporting the wafer, which are mounted into the MPSB during etching
  • The Porous Silicon Power Supply PS², which provides the large electrical currents needed for PS formation

Together, these products form a turn-key system for porous silicon etching, which is used by major players in the MEMS field.

For details please see the product pages.


Click to enlarge

  • porous silicon

    Figure_ n+ -type porous silicon made by anodization at 250 mA/cmin the dark in an ethanoic/HF bath: (left) SEM porous silicon front view; (right) SEM porous silicon cross-section view.