Abstract
To reduce smear, a highly resistive MCZ Si substrate is applied to 384H×491V Interline Transfer (IT) CCD Imager.
Since MCZ Si crystal has good controllability of interstitial oxygen concentration and its uniformity, it is possible to use it for highly resistive Si substrate without thermal donor conversion problems.
Measured smear signal levels at 650nm wavelength are 1%, 0.5% and 0.2% for signal level for 12ohm-cm, 40ohm-cm and 120ohm-cm substrates, respectively.
To achieve more effective smear reduction, the P-well was introduced under vertical shift registers. The smear level was reduced to less than 1/10 that of non-P-well devices. Thin poly Si-SiO2-Si (MOS) sensor structure is also used in this device.
The MOS sensor has no lag characteristics due to complete signal charge transfer into vertical shift registers. Also, it has high spectral sensitivity by the choice of optimum interference effect between thin poly Si-SiO2-Si structures.
