Here - Revision history

Chris at 11:35, 5 May 2021

2021-05-05T11:35:02Z

← Older revision		Revision as of 19:35, 5 May 2021
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	[[File:Silicon-thickness.png\|800px]] [[File:Substrate-BK7.png\|720px]]		[[File:Silicon-thickness.png\|800px]] [[File:Substrate-BK7.png\|720px]]

			'''Comment''': Hmmm, good to have a characterization of the growth speed :) However, the transmission of the BK7 window in the near-visible regime seems a bit low...? I also don't understand the scale on the right vertical axis...

Yicheng: /* Silicon Coating Speed Calibrating */

2021-04-30T14:55:59Z

Silicon Coating Speed Calibrating

← Older revision		Revision as of 22:55, 30 April 2021
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	We took an optical method approach by observing the change in transmission spectrum for different deposition time (which should translate to different thickness if a constant deposition rate is assumed). We deposited a few different thin-film samples, with deposition time of 6000s, 8000s, 10000s, 12000s. The transmission spectrum of each sample is measured with a spectrophotometers. From the measured spectra we roughly estimated a deposition rate of 0.034nm/s (2.05nm/min).		We took an optical method approach by observing the change in transmission spectrum for different deposition time (which should translate to different thickness if a constant deposition rate is assumed). We deposited a few different thin-film samples, with deposition time of 6000s, 8000s, 10000s, 12000s. The transmission spectrum of each sample is measured with a spectrophotometers. From the measured spectra we roughly estimated a deposition rate of 0.034nm/s (2.05nm/min).



	[[File:Silicon-thickness.png\|800px]] [[File:Substrate-BK7.png\|720px]]		[[File:Silicon-thickness.png\|800px]] [[File:Substrate-BK7.png\|720px]]

Yicheng at 14:55, 30 April 2021

2021-04-30T14:55:27Z

← Older revision		Revision as of 22:55, 30 April 2021
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	=Silicon Coating Speed Calibrating=		=Silicon Coating Speed Calibrating=
	~~Sputtering speed depends not only on the input~~ RF ~~power but also related to the distance between the target and the sample~~. ~~and the surface area of the sample~~. ~~We have to calibrate the~~ sputtering ~~speed~~ to ~~make sure the thickness~~ of ~~the film we coated is correctly equal to a quarter lambda or a half lambda. We sputtered~~ silicon ~~film on~~ the optical window to ~~measure~~ the ~~thickness of different~~ sputtering ~~time. In~~ this ~~calibration experiment, we are using 100w power for RF signal~~, and the ~~distance between~~ the ~~target and~~ the ~~sample is about 8cm, while the diameter of~~ the ~~glass (Optical Window) is 25~~.~~4mm. We tried for 6000s, 8000s, 10000s, 12000s, 20000s. </p><p>~~		We have tentatively tried to operate a RF sputtering machine<ref>https://www.dentonvacuum.com/products-technologies/magnetron-sputtering/</ref> to deposit a thin layer of silicon onto the surface of an optical window made of BK7 glass. This machine generates a powerful (>100 Watt) RF electric field to ionize the Argon gas in the chamber. This ionized argon gas will then bombard the sputtering targets (silicon in this case), and the sputtered atoms from the targets will in turn form the deposition layer on the substrate.

	~~[[File:Silicon-~~thickness.~~png\|800px]] </p><p>~~		The deposition rate (how fast does the layer grow, usually in nm/s) depends not only on the input RF power, but is also related to the distance between the sputtering targets and the substrate sample as well as the surface area of the sample. This deposition rate needs to be measured as accurate as possible to ensure correct layer thickness.

	The ~~estimated speed~~ is ~~drawn in~~ the ~~graph with dashed lines~~.</~~p><p>~~		We took an optical method approach by observing the change in transmission spectrum for different deposition time (which should translate to different thickness if a constant deposition rate is assumed). We deposited a few different thin-film samples, with deposition time of 6000s, 8000s, 10000s, 12000s. The transmission spectrum of each sample is measured with a spectrophotometers. From the measured spectra we roughly estimated a deposition rate of 0.034nm/s (2.05nm/min).
	[[File:Substrate-BK7.png\|720px]]
			[[File:Silicon-thickness.png\|800px]] [[File:Substrate-BK7.png\|720px]]

Yicheng: /* Silicon Coating Speed Calibrating */

2021-04-30T14:27:23Z

Silicon Coating Speed Calibrating

← Older revision		Revision as of 22:27, 30 April 2021
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	==Silicon Coating Speed Calibrating==		=Silicon Coating Speed Calibrating=
	Sputtering speed depends not only on the input RF power but also related to the distance between the target and the sample. and the surface area of the sample. We have to calibrate the sputtering speed to make sure the thickness of the film we coated is correctly equal to a quarter lambda or a half lambda. We sputtered silicon film on the optical window to measure the thickness of different sputtering time. In this calibration experiment, we are using 100w power for RF signal, and the distance between the target and the sample is about 8cm, while the diameter of the glass (Optical Window) is 25.4mm. We tried for 6000s, 8000s, 10000s, 12000s, 20000s. </p><p>		Sputtering speed depends not only on the input RF power but also related to the distance between the target and the sample. and the surface area of the sample. We have to calibrate the sputtering speed to make sure the thickness of the film we coated is correctly equal to a quarter lambda or a half lambda. We sputtered silicon film on the optical window to measure the thickness of different sputtering time. In this calibration experiment, we are using 100w power for RF signal, and the distance between the target and the sample is about 8cm, while the diameter of the glass (Optical Window) is 25.4mm. We tried for 6000s, 8000s, 10000s, 12000s, 20000s. </p><p>

Yicheng at 14:24, 30 April 2021

2021-04-30T14:24:47Z

← Older revision		Revision as of 22:24, 30 April 2021
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	[[File:~~temperature_shift~~.png\|~~options~~\|]]		==Silicon Coating Speed Calibrating==
			Sputtering speed depends not only on the input RF power but also related to the distance between the target and the sample. and the surface area of the sample. We have to calibrate the sputtering speed to make sure the thickness of the film we coated is correctly equal to a quarter lambda or a half lambda. We sputtered silicon film on the optical window to measure the thickness of different sputtering time. In this calibration experiment, we are using 100w power for RF signal, and the distance between the target and the sample is about 8cm, while the diameter of the glass (Optical Window) is 25.4mm. We tried for 6000s, 8000s, 10000s, 12000s, 20000s. </p><p>

			[[File:Silicon-thickness.png\|800px]] </p><p>

			The estimated speed is drawn in the graph with dashed lines.</p><p>
			[[File:Substrate-BK7.png\|720px]]

Yicheng: Created page with "options|"

2021-03-09T05:54:47Z

Created page with "options|"

New page

[[File:temperature_shift.png|options|]]