A NEW TECHNOLOGY FOR MICROMACHINING OF SILICON - DOPANT SELECTIVE HF ANODIC ETCHING FOR THE REALIZATION OF LOW-DOPED MONOCRYSTALLINE SILICON STRUCTURES

In this letter, we report on the use of the sharp selectivity of HF anodic etching between p-Si and n-Si to realize monocrystalline silicon microstructures, in this case suspended beams, making use of masked implantation of phosphorous for the definition of the geometry. We are convinced that this technology offers new opportunities in the field of micromachining of silicon for micromechanical applications. The technology is complementary to bulk micromachining (anisotropic KOH or EDP etching, or isotropic HF/HNO3 etching) and surface micromachining with sacrificial-layer techniques. © 1990 IEEE