| 摘要 |
PURPOSE:To seek to improve the characteristics to maintain information of a semiconductor storage device by separating transfer MISFETs by means of a field insulating film using a groove deeper than those source and drain. CONSTITUTION:An n-type well region 2 is provided at the main face of a semiconductor substrate 1, and a field insulating film 3 is provided around a memory cell region at the main face of the n-type well region 2. Since a field insulating film 3 is constituted by burying an insulating film 4 in a groove deeper than the depths of the source 11 and the drain 12 of an n-channel MISFET at the main face of a semiconductor substrate 1, fellow transfer MISFETs are separated favorably from each other. If photoelectrons generated at the end of a drain region 11 enter a gate insulating film 10, the photoelectrons act on a channel region 20 to elevate the threshold, and they act on a source 11 and a drain 12 to reduce the leakage currents between them. Hereby, the characteristics to maintain information of a semiconductor storage device can be improved. |
