Experimental characterization of transfer Efficiency in charge-coupled devices

The most important characteristic of a charge-coupled device is its charge transfer efficiency (CTE). There are three basic types of loss which degrade CTE: fixed loss, proportional loss, and nonlinear loss. Examples are given of each type of loss and techniques for measurement of all three types of loss are described. A method of determining the minimum fat zero which eliminates fixed loss is shown and an experiment is presented which confirms that fixed loss due to surface states can be completely eliminated by the use of a fat zero. The effect of interelectrode gaps on CTE is discussed in detail. A nonlinear loss model is used to describe the dispersion due to barriers in the gaps and the very detrimental effect of wells in the gap region is shown. The techniques presented in the analysis of these losses are very general and can be used whenever a detailed description of the transfer loss mechanism is required.