Tuesday, September 22, 2015

Black Silicon Presentation

Eric Mazur, Harward University Professor, Black Silicon inventor, and SiOnyx founder, publishes his presentation on Black Silicon properties and applications given at the 11th Conference on Lasers and Electro- Optics Pacific Rim (CLEO-PR 2015) in Busan, South Korea on 25 August 2015. Black Silicon is manufactured by high power laser treatment of the silicon surface and looks like this:


A TEM cross-sectional image reveals an interesting picture. It's scary to think that SiOnyx made image sensors out of this:

13 comments:

  1. Does anyone know the photodiode dark current at 60 C?

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    1. SiOnyx slide in the post gives dark current numbers, but does not state the temperature.

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  2. These slides which compares Sony CCD sensor with SiOnyx sensor are worst presentations I have ever seen in my life.

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    1. Could you elaborate your reasons for saying so? Here's my critique of those slides:

      The first comparison slide seems to just show stronger chrominance signal than Sony. Don't know why a stronger CCM can't make Sony similar. Is there color noise?

      The second comparison slide shows lots of false color on the Sony. Likely demosaicking issues, not sensor. The tone mapping is not the same. But I do see a difference in dynamic range, assuming it hasn't been artificially clipped.

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    2. The false color is only present in high contrast areas with clipped highlights. This is a common demosaicking issue. The highlight clipping creates a sharp edge - sharper than the optics can create. This stresses the demosaicker and causes some algorithms to break out into false colors.

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  3. Any one has idea on how this treatment be applied to PPD ?

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    1. I thought it use the surface for convertion, so PPD do not work for this.

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  4. The test scenes have changed in between the tested cameras/sensors, and in the last comparison the shadow of the car indicates the images is taken at different parts of the day, giving very different lighting. Not at all a fair or good comparison. This is a demonstration on how not to compare.

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    1. At first I was going to say the 2 hour difference probably didn't matter but on closer inspection (look at the shadow cast by the block on the window) its clear that much more light is entering the office which would naturally light up the darker areas and lower the dynamic range of the overall photo. I imagine differences are due to set up time or access to the camera at specific times and is not purposefully misleading but a nice controlled picture would be nice.

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  5. The absorption of black silicon at 1100nm~2500nm is too flat. Does this mean that energy levels induced by interface or defects in the black silicon have a very uniform distribution in the energy band? ... It seems weird to me.

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    1. Sadly it is still just a plot of absorption and not QE, may things are good absorbers of light!

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  6. If I understand well, there are two phenomena in black silicon: one is the S doping and the other is laser ablated surface. In a normal black silicon based PN junction photodiode, only the S doping is used, where S acts as donor. Am I right ?

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  7. Why compare to Sony CCD? Have chosen this imager for a reason.

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