ENABLING THE CONTROLLED ELECTROCHEMICAL ETCHING OF HIGH-ASPECT-RATIO SUBMICROMETRIC PORES IN LOW-DOPED N-TYPE SILICON USING HIGH ANODIC VOLTAGE

Here, we report on the controlled electrochemical etching at high anodic voltage (up to 40 V) of ordered arrays of pores with submicrometric diameter (down to 800 nm) and high aspect ratio (up to 50), in low-doped (resistivity 3-8 ? cm) n-type silicon. It is shown that by increasing the anodic voltage of one order of magnitude, with respect to the typical value of about 2 V, it is possible to circumvent constraints in back-side illumination etching of highly packed (pitch <2 ?m) and submicrometric (diameter <1 ?m) pores on standard low-doped silicon substrates commonly used in the microelectronic industry and scale-down both pitch and diameters of pores to unprecedented values. Experimental results clearly envisage the possibility of fabrication of submicrometric structures and systems for novel applications in photonics and microelectronics.