Generation and transport of contamination in high current implanters

Blake, J.; Jones, Mary Ann; Meyyappan, N.; Hirokawa, S.; Sato, M.

doi:10.1016/0168-583x(94)00454-4

Cited by 9 publications

(2 citation statements)

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“…For a CIS fabrication process, in particular, the tungsten contamination is able to be originated from tungsten-film chemical vapor deposition, tungsten-film chemical mechanical planarization, or ion implantation process. [3][4][5][6][7][8] In particular, it was reported that the concentration of tungsten impurity was the range of 10-110 ppm. 9) In addition, the tungsten contamination has been speculated as a major root-cause for inducing white spots since the tungsten contaminant has an extremely low diffusivity in a silicon wafer so that they are located in the photodiode region in a CIS cell after a CIS fabrication process.…”

Section: Introductionmentioning

confidence: 99%

Impact of tungsten contamination on the sensing margin of a CMOS image sensor cell

Song¹,

Kim²,

Lee³

et al. 2014

Jpn. J. Appl. Phys.

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We investigated the impact of tungsten contamination on minority-carrier recombination lifetime, the photodiode dark/photo current and sensitivity of a pinned photodiode, and the sensing margin of a CMOS image sensor (CIS) cell. After an intentional tungsten contamination and followed by driving at 800 °C for 30 min, tungsten contaminant were located from the surface to p-and n-type regions of a photodiode. The tungsten contamination degraded minority-carrier recombination life-time and the dark current and sensitivity of a pinned photodiode; i.e., there was a good correlation between the minority recombination lifetime and the sensitivity of a photodiode. As a result, tungsten contamination directly degraded the sensing margin of a CIS cell photodiode; i.e., it decreased with increasing tungsten contaminant concentration.

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Section: Introductionmentioning

confidence: 99%

Impact of tungsten contamination on the sensing margin of a CMOS image sensor cell

Song¹,

Kim²,

Lee³

et al. 2014

Jpn. J. Appl. Phys.

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“…Aluminum is tolerant in sense of electric characteristics of devices at somewhat higher levels than heavy metals, but Aluminum contamination must be minimized, needless to say. It is common practice to protect metal surfaces from direct beam strike by Silicon coating [ 2 ] .…”

Section: Introductionmentioning

confidence: 99%

Monitoring system for silicon coating thickness of disk

Kawaguchi¹,

Kabasawa²,

Tsukihara³

et al.

2000 International Conference on Ion Implantation Technology Proceedings. Ion Implantation Technology - 2000 (Cat. No.00EX432)

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In batch ion implanters, wafers are set on a rotating wafer-disk which has a metal surface exposed to ion beams. In order to reduce metal contamination from the disk, the metal surface is usually coated by Silicon. Because implantation is done to the disk surface as well as wafers, the surface is sputtered and the Silicon coated layer becomes thinner by degrees. When the Silicon coated layer is removed by sputtering, the base disk material (usually aluminum alloy) is exposed to the ion beam, and thus metal contamination increases. Therefore, it is necessary to monitor the thickness of the Silicon coated layer and to estimate the remaining thickness.There is a charge sensor on a wafer-disk in ion implanters. This system consists of a sensor on the surface of disk and a detection circuit, and measures charging voltages during implantation. It is known that output of the charge sensor depends on a material of the sensor surface. After coating the surface of the sensor by Silicon, correlation between the thickness of Silicon coated layer of the sensor and the output of the sensor was measured. It is found that this in-situ monitoring system can detect the marginal thickness of Silicon coated layer precisely.

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