The influence of bulk traps on the charge-transfer inefficiency of bulk charge-coupled devices

One of the possible causes of a finite charge-transfer inefficiency in bulk charge-coupled devices (BCCD´s) is the presence of bulk traps in the n-type silicon layer through which the charge packets are transferred. To determine the relative importance of the contribution of traps, we measured charge transfer inefficiency as a function of temperature. In most of the devices investigated, this measurement results in two broad peaks due to the presence of traps at 0.25 and 0.54 eV below the conduction band edge. The concentration of these traps varied from batch to batch between values of 5 × 10¹⁰cm^-3and 1 × 10¹²cm^-3.