Technologies for porous silicon devices

Abstract

For making porous silicon devices, it is important to study the overall effect of important processing steps on this material. This paper deals with the most important steps required for fabricating discrete devices and also for integration with silicon integrated circuits. A p-n junction has been formed in porous silicon by diffusion at high temperatures and it has reduced the resistance of the material. A new technique has been developed, which is known as waxolithography, for making small structures in this material. The metallic structure has also been optimized for good ohmic contact. Optical propetties of porous silicon are also discussed.

Silicon Porosification: State of the Art

“…This type of etch stop was used, for example, for SOI (silicon on insulator) structures made by oxidizing porous silicon. 155 Stopping at a p-n junction was also reported by Gupta et al 375 Another possibility is the use of n − -n + -type (or p − -p + -type) iso-junctions. 155 As established by Eijkel et al, 376 in the absence of light generation the rate of pore formation in p-and n-type silicon with concentration of free charge carriers smaller than 10 16 cm −3 is very low.…”

Formation and characterization of porous silicon films obtained by catalyzed vapor-chemical etching

“…In the literature there are a large number of papers focused on Porous Silicon (PS) formation and its optical, insulating and chemical sensing applications [1]. The ability of the PS to adsorb gaseous species [2] is due to its high surface chemical activity and a great surface to volume ratio greater than 200 m 2 /cm 3 [3], which is suitable for sensing applications.…”

Optical properties of porous Si/PECVD SiNX:H reflector on single crystalline Si for solar cells

“…This entails an important rise of refractive index compared to silicon substrate (3.78), which can lead to an increase in the reflectivity greater than 70 %. However, the stability of the porous layer requires a porosity value not exceeding 65 % that corresponds to a refractive index of 1.93 [28][29][30]. In that case, the calculation resulted in a designed thickness of approximately 92 nm for a refractive index equal to 1.90, corresponding to a porosity of 60 %.…”