MANUFACTURE OF SEMICONDUCTOR DEVICE

PURPOSE:To miniaturize the title device and to diminish ON-resistance by making the angle of incidence of a beam to a substrate smaller than the angle of incidence of a beam to the substrate in the implantation of impurities for forming a high-concentration region for making contact with a well region. CONSTITUTION:When the angle between a line connecting the upper end of a right side gate edge and the lower end of a left side gate edge and a substrate 19 surface is theta1 and the angle between a line connecting the upper end of the right side gate edge and the center of a diffusion window surface and the substrate 19 surface is theta2, the angle theta between an ion beam and the substrate 19 surface is smaller than theta1. Therefore, little impurities are implanted into the diffusion window. Also, when the angle theta between the ion beam and the substrate 19 surface is larger than theta1 and smaller than theta2, the ions are implanted only into the left side of the diffusion window. Thus, it is possible to obtain a small-sized vertical MOS transistor with little ON-resistance.