SEMICONDUCTOR DEVICE AND MANUFACTURE OF THE SAME

摘要

PURPOSE:To prevent p-n junction of a protection diode from being destroyed by surge by a method wherein when a transistor and the diode are formed on one semiconductor substrate an impurity containing gate electrode of the transistor is made touch one end of the diode region and a deep diffusion is formed to that end part by thermal treatment. CONSTITUTION:A p type Si substrate 11 is divided into an MOS transistor element region and a protection diode element region by a thick field oxide film 12. A polycrystalline Si layer is formed on the transistor region via a gate oxide film 13 and its resistance is reduced by doping P. Then the Si layer is patterned and a gate electrode 14 of the transistor is formed while being made touch directly one end of the diode region. An As doped glass layer 15 is formed on the whole surface including the gate electrode. After that, n<+> type source drain regions of the transistor which are not shown in figures are formed by diffusing As by thermal treatment and simultaneously an n<+> type region 16 is formed on the diode region and at the same time a deep n<+> type region made by P is formed to that end part by utilizing the difference of diffusion coefficients.