Document Type
Thesis
Date of Award
12-31-1988
Degree Name
Master of Science in Electrical Engineering - (M.S.)
Department
Electrical Engineering
First Advisor
Walter F. Kosonocky
Second Advisor
Constantine N. Manikopoulos
Third Advisor
Yun Q. Shi
Abstract
Buried channel charge coupled devices used as readout registers in PtSi Schottky-barrier detector infrared image sensors were investigated to characterize factors that influence charge transfer efficiency at low temperatures ranging from 38 to 80K. These factors included frequency of operation, background signal, gate voltage, signal level, gate length, and temperature. It was found that increased gate voltage and decreased gate length are most effective in reducing charge transfer efficiency. This was attributed to increased fringing fields between the potential wells involved in charge transfer. As temperature was decreased from 50K to 38K progressively larger trapping losses were observed due to carrier freeze-out in the buried-channel. With the application of higher gate voltages the observed carrier freeze-out was reduced due to the lowering of the activation energy of the traps by the Frenkel-Poole effect. It was also found that an additional trench implant in the buried-channel reduces charge transfer inefficiency for small signals as well as large signals. The trench implant also lowers operating temperature by 5 to 10K with acceptable transfer loss. For operation of a two-phase buried-channel register with additional trench implant, 10-um gate lengths (40-um stages), and a background charge equal to 5x104 electrons, the charge transfer inefficiency was found to be 5x10-5 per transfer at 77K and 3x10-3 per transfer at 55K. Based on the results obtained, a new charge coupled device gate structure was proposed for reducing low temperature charge transfer efficiency.
Recommended Citation
Esposito, Benjamin Benjamin, "Charge transfer inefficiency of buried-channel charged coupled device registers for low temperature operation of PtSi infrared image sensors" (1988). Theses. 3066.
https://digitalcommons.njit.edu/theses/3066
