| 摘要 |
PURPOSE:To shorten the time taken from writing of information to completion of a mask ROM by providing an island region of a thin film of single crystal semiconductor island region with a MOS transistor on one side and by introducing impurity from the other side to write information. CONSTITUTION:A plurality of gate electrodes 5 are formed in parallel via an insulating film 8 on one main face of a single crystal semiconductor island region 3 consisting of a thin film, and source-drain regions 6a-6g are formed in the single crystal semiconductor island region 3. Impurity is introduced selectively into the channel-forming region of a MOS transistor according to information from the other side of the island region 3, thereby creating enhancement type transistors Q2, Q4, Q7, Q8, T2, and T3 and depletion type MOS transistors Q1, Q3, Q5, Q6, T1, and T4. This introduction of impurity requires no ion implantation for example at high energy because the single crystal semiconductor island region 3 is a thin film. This design can shorten the time taken from writing of information to completion of a mask ROM. |
