| 摘要 |
PURPOSE:To form an ideal electrostatic breakdown preventive diode having small dynamic resistance by deeply shaping a reverse conduction type region so as to form a P-N junction with a buried region. CONSTITUTION:A P type diffusion layer 8A formed at the same time as a P type isolation region 8 is shaped, and a P-N junction 12 is formed between the diffusion layer 8A and an N type buried layer 6 in high concentration. Consequently, the resistance section of an N type epitaxial layer 7 can be removed, and the dynamic resistance of a diode can be lowered. Since the P-N junction 12 is shaped by the high concentration region 8A and 12, withstanding voltage reaches to 30-40V, and withstanding voltage proper as the diode for preventing electrostatic breakdown is obtained. An N type diffusion layer 11 in concentration higher than the epitaxial layer 7 is formed so as to be connected to the N type buried layer 6 in order to further lower the dynamic resistance of the diode and further display a protecting effect, thus also lowering one resistance section R4 of the N type epitaxial layer 7. |
