| 摘要 |
PURPOSE:To obtain a rewritable ROM featuring the reduced power consumption and a proper input/output voltage level by providing the memory transistor and the transistor within the isolated island-shaped region plus the transistor complementary to the above mentioned transistors within the isolated region each. CONSTITUTION:P-type layer 2 is epitaxial-grown on N-type Si substrate 1, and N- type region 3 forming a closed circuit is formed by diffusion there until it reaches substrate 1. Layer 2 is then separated into island 2a and 2b. Then N<+>-type source and drain regions 41 and 51 are formed by diffusion within island-shaped layer 2a, and gate 81 is provided between region 41 and 51 via SiO2 film 61 and Si3N4 film 71 each. Thus, an N-channel MNOS memory transistor is formed. In the same method, the N-channel MOS transistor is formed within island region 2b, and P<+>- type source and drain regions 43 and 53 plus the P-channel element composed of gate electrode 73 via SiO2 film 63 are formed within isolated region 3. |
