| 摘要 |
PURPOSE:To obtain sufficient voltage difference margin of a charge coupled element and to prevent the deterioration in the transfer efficiency of the element by providing the maximum voltage in the buried channel in a region capable of obtaining preferable transfer efficiency in the characteristics of the maximum voltage vs. transfer efficiency in the buried channel under a transfer electrode. CONSTITUTION:When the thickness of a buried channel 4 is set to 0.4-0.5mum, the thickness of an insulating film 2 is, for example, approx. 1,000Angstrom , transfer electrodes 31-3n are driven by 2-phase clock, 2-phase clock is 0V at low level and 9V at high level and clock frequency is 7MHz, the relationship between the maximum voltage in the channel under the transfer electrode when the transfer electrode is 0V and the transfer efficiency per one transfer stage is as shown by a characteristic curve 1. Accordingly, as apparent from the curve 1, when the impruity density of the buried channel 4 is selectively set so that the channel voltage becomes approx. 5V or higher, sufficient voltage difference margin can be obtained, mutual action between the boundary level and the transfer charge does not exist, and preferable transfer efficiency can be obtained. |
