25 May 2004 The low-frequency noise of HgCdTe sensor with overlap structure
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Proceedings Volume 5472, Noise and Information in Nanoelectronics, Sensors, and Standards II; (2004); doi: 10.1117/12.546644
Event: Second International Symposium on Fluctuations and Noise, 2004, Maspalomas, Gran Canaria Island, Spain
Abstract
The minor carrier effective lifetime of middle wavelength infrared HgCdTe photoconductive sensors is relatively large. The sweep-out effect may easily emerge in small size sensors which decrease the responsitivity. In order to eliminate this effect, an overlap structure is often used. In this paper the low frequency noise characteristics of HgCdTe sensors with this overlap structure is studied. It is shown that not only the low frequency noise of sensors with this overlap structure is much larger than that of the conventional ones, but also Hooge parameter and frequency exponent are changed with bias current especially for this overlap structure. An edge-contacted asymmetrical metal-insulator-semiconductor model is presented to explain the noise characterization. It is found that a depletion layer would appear from the HgCdTe surface under overlap electrodes when the sensors are biased. Its thickness changed with its position because of the difference of the voltage. When the bias current is increased, this depletion layer is widening. Also Hooge parameter and frequency exponent increased which are similar to the MISFETs. It is shown by experiments that the enhancement of sensor noise for overlap structure is mainly caused by the depletion layer under overlap electrodes.
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Yan Zhang, Jiaxiong Fang, "The low-frequency noise of HgCdTe sensor with overlap structure", Proc. SPIE 5472, Noise and Information in Nanoelectronics, Sensors, and Standards II, (25 May 2004); doi: 10.1117/12.546644; https://doi.org/10.1117/12.546644
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KEYWORDS
Sensors

Mercury cadmium telluride

Electrodes

Infrared sensors

Metals

Infrared radiation

Infrared photography

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