Study of Thick Microporous Silicon Layer from Highly Resistive Silicon

Abstract

Porous silicon (PS) formed from low doped silicon is reported to be a promising material for power electronic applications for electrical insulating. However, post-anodization steps on porous silicon, such as photolithography or metallization require the implementation of smooth porous silicon surfaces. In the present work, we use low doped (30-50 Omegacm) p-type Si. Our experiments allowed us the implementation of structures with pore dimensions extending from some micrometers (macroporous PS) to few nanometers (microporous Si). The use of a particular solution based on HF-H2O and acetic acid permitted to achieve microporous Si structures. The evaluation of the porosity versus the thickness is found to be a pertinent parameter to study the structure integrity of the so formed microporous silicon. Thus, layers with a thickness up to 400 microm have been implemented with a porosity of 50%.

Porous silicon fabrication by anodisation: Progress towards the realisation of layers and powders with high surface area and micropore content

“…Two different resistivities were utilised in the expectation of achieving M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT small pore diameter: 1-5 ohm.cm [8] and 30-50 ohm.cm [11,12]. Anodisation was possible after rendering the rear sides of these wafers ohmic via boron diffusion at 1050°C for 1 hour.…”

Systematic Study of Anodic Etching of Highly Doped N-type 4H-SiC in Various HF Based Electrolytes

“…56:26:18. Compared with ethanol, this solvent is known to change the morphology only in the case of highly resistive substrates 22. Indeed, instead of large macropores, mesopores are observed in low doped p type silicon if acetic acid is added to the electrolyte.…”

Thick microporous silicon isolation layers for integrated RF inductors

“…The samples obtained under these conditions are microporous. More experimental details were presented in previous work [5].…”