Heavy Metal Gettering in Silicon‐Device Processing

Baldi, L.; Cerofolini, G. F.; Ferla, G.

doi:10.1149/1.2129609

Cited by 54 publications

(19 citation statements)

References 2 publications

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“…However, as the variation in the film thickness is not large (70–115 nm) and d SiN x is similar if Fe is concentrated at the SiN x /Si interface, we suspect that the different Fe concentration ratios at 400 °C likely reflect the different gettering capacities of the SiN x films, that is, the different segregation coefficients. According to refs and , the segregation coefficient of Fe from Si into SiN x can be described in the form of where N SiN x is the concentration of the gettering sites in the SiN x film, N Si is the number of Si atoms per unit volume, k is the Boltzmann constant, and E Fe,Si and E Fe,SiN x are the activation energies associated with the solubilities of Fe in Si and in the SiN x gettering region, respectively. As K ( T ) is expected to be much larger than 1 due to the very large difference in the thicknesses of the Si wafer bulk and the SiN x gettering region ( i.e.…”

Section: Resultsmentioning

confidence: 99%

Impurity Gettering by Silicon Nitride Films: Kinetics, Mechanisms, and Simulation

Hameiri

Truong

et al. 2021

ACS Appl. Energy Mater.

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Metallic impurities in the silicon wafer bulk are one of the major efficiency-limiting factors in silicon solar cells. Gettering can be used to significantly lower the metal concentrations. Although gettering by silicon nitride films has been reported in literature, much remains unknown about its gettering behaviors and mechanisms. In this study, the gettering kinetics and mechanisms of silicon nitride films, from both plasma-enhanced chemical vapor deposition (PECVD) and low-pressure chemical vapor deposition (LPCVD), are investigated. By monitoring the kinetics of iron loss from the silicon wafer bulk, it is confirmed that silicon nitride gettering takes place mainly via segregation, even at a low annealing temperature of 400 °C. Simulation of the gettering kinetics suggests the presence of an interfacial diffusion barrier in some cases, which slows down the transport of iron impurities from the silicon wafer bulk to the silicon nitride gettering regions. The activation energy of the segregation gettering process is estimated to be 0.9 ± 0.1 eV for the investigated PECVD silicon nitride film at 400–900 °C and 1.6 ± 0.5 eV for the investigated LPCVD silicon nitride film at 400–700 °C.

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Section: Resultsmentioning

confidence: 99%

Impurity Gettering by Silicon Nitride Films: Kinetics, Mechanisms, and Simulation

Hameiri

Truong

et al. 2021

ACS Appl. Energy Mater.

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“…The effectiveness of phosphorus as a gettering agent was first recognized in 1960 [11], and has been extensively studied [12][13][14][15][16][17][18]. By the use of in-situ doped polysilicon, both polysilicon and phosphorus are present on the back side of the wafer for gettering.…”

Section: Detector Fabrication and Experimental Resultsmentioning

confidence: 99%

An IC-compatible detector process

Holland

1989

IEEE Trans. Nucl. Sci.

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A silicon radiation-detector fabrication process which exploits the excellent gettering properties of a backside layer of phosphorus-doped poly silicon has been developed and characterized. 2 !DID diameter pi-n diodes have been fabricated with typical reversebias current densities of approximately 1 nAlcm 2 • In addition, a strip detector with 128 strips of 6 !DID length on a 55 ~m pitch has been successfully fabricated with better than 10% uniformity in the diode reverse-bias currents. The process is compatible with conventional integrated-circuit fabrication technologies, and p-channel enhancement and depletion-mode MOSFETs with associated inter-device isolation have been fabricated simultaneously on detector-grade silicon with p-i-n radiation detectors.

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“…Phosphorous gettering (3,4) and care to avoid processing s teps above 1000 •c have yielded long lifetimes in conventional cells processed at Sandia (5,6) and similarly in this cell structur e . A low front surface recombinatio n velocity was obtained by growing a 300 A-thick front surface thermal oxide followed by a forming gas anneal at 450°C, The forming gas anneal is essential to ' good surface passivation.…”

Section: The Ibc Structu Re and Fabricationmentioning

confidence: 99%