Chip Grade and Blemishes

For the charge packet of the topmost row of pixels, readout requires passing through all pixels in the same column. If a pixel in a column cannot form a potential well, or the formed potential well is defective, the charge packets of pixels in rows above it cannot be transferred out or are only partially transferred. This is one type of defect.

Pixel photosensitivity failure, or reduced quantum efficiency, is also a type of defect.

The types of defects are classified as:

^{Traps: Pixels where charge is temporarily held. Traps are counted if they have a capacity greater than 200 e− at 253 K.}

Point defects:

      Black Spot: Are counted when they have a signal level of less than 80% of the local mean at a signal level of approximately half full-well. Under half-full-well conditions, pixels with a count value below 80% of the average of surrounding pixels.

      White Spot: Are counted when they have a generation rate 125 times the specified maximum dark signal generation rate (measured between 253 and 293 K). Pixels with an electron generation rate 125 times the maximum dark current specification (measured over 253 K to 293 K).

Column defects: A column which contains at least 50 white or 50 black defects. A column with more than 50 black or white spots.

Column defects A column which contains at least 50 white or 50 black defects.

Grade 5 Devices which are fully functional, with image quality below that of grade 2, and which may not meet all other performance parameters.

Note: The effect of temperature on defects is that traps will be observed less at higher temperatures but more may appear below 253 K. The amplitude of white spots and columns will decrease rapidly with temperature.

Greateyes provides defect grades based on the chip manufacturer's chip grade, typically Grade 0 or Grade 1.

The above content was compiled and collected by Jerry Huang of our company, for the purpose of knowledge sharing and mutual learning only, and shall not be reproduced without permission.