Gettering impurities from crystalline silicon by phosphorus diffusion using a porous silicon layer

Studies of the oxidation states of phosphorus gettered silicon substrates using X-ray photoelectron spectroscopy and transmission electron microscopy

“…This value fits well with the reported binding energy of 135.3 eV for P 4 O 10 . 16 It should be mentioned here that at this depth (4-11 nm), the O(P 3 ) peak of the O1s was observed which was assigned to P 4 17 In the present work, the energy separation between the peak P-2p 3=2 and Si-2p 3=2 is used to monitor the relative positions of the two peaks with depth. An increase of the P-2p 3=2 -Si-2p 3=2 energy separation implies either a reduced screening of the P-2p 3=2 and/or an increased screening of the Si-2p 3=2 .…”

“…This is widely used in solar cell processing. 3,4 These impurities can enhance recombination processes and reduce lifetime of charge carriers and solar cell efficiency. 5 Reducing P 2 O 5 to elemental P in the surface region of the Si wafer can cause the concentration briefly to exceed that of a saturated solid solution.…”

The impact of thermal treatment on gettering efficiency in silicon solar cell

“…Although the problem of precipitates in principle has been eliminated, the purity effectiveness depends on the establishment of gettering sites for absorbing impurities, the diffusion coefficients of the impurities in bulk Si, and the segregation coefficient of the impurities at the gettering sites [27][28][29][30].…”

Porous Silicon and Solar Cells

“…Possibility of the conversion of high-energy ultraviolet and blue part of the solar spectrum into long-wavelength radiations due to photoluminescence in nanocrystalline porous silicon (Svrcek et al 2004) 5. Surface passivation and gettering role of porous silicon (Weiying et al 2011;Ben Rabna et al 2013;Solanki et al 2004;Khedher et al 2005) 6. Simplicity and lower cost of fabrication technology of nanoporous silicon due to electrochemical modification of silicon There are two types of technology of formation of porous silicon layer on silicon solar cells: (1) the thin porous silicon is formed in the final step on the surface of ready Si solar cell with metal contacts and (2) the relatively thick porous silicon layer is formed prior to emitter diffusion and metal contact deposition.…”