| 摘要 |
PURPOSE:To reduce the poly Si resistance of MOS type semiconductor by a method wherein the As concentration in poly Si bipolar semiconductor is precisely controlled to control the characteristics thereof. CONSTITUTION:A P type Si substrate 1 is divided into two regions A and B by an SiO2 layer 2. In the region A, a P layer 4 is provided on an N layer 6 with an N<+> layer 3 buried therein and then the N<+> layer 3 is connected to another N<+> layer 5 while openings 9, 10, 11 are selectively made on an SiO2 film 7. In the region B, a gate oxide film 8 is formed on an N layer 4. Next overall surface is covered with a poly Si thin film 12 and then the part near the interface to the substrate 1 is implanted with As ion at high concentration with excellent controllability. Furthermore, another Si thin film 13 is deposited on the film 12 so that the part near the interface to the substrate 1 may be implanted with As ion having no influence thereon. Then openings are made into the layers 12, 13 selectively utilizing resist masks 14 to be implanted with B ion for forming P<+> layers 15 and then the masks 14 are removed to cover the overall surface with SiO2 16 and then heated to form an N type As diffusion layer 17. Finally openings are made into the SiO2 film 16 utilizing another resist mask 18 to form Al electrode 19. Through these procedures, the substrate may be As diffused with high precision simultaneously reducing any poly Si resistance to achieve the acceleration of device improving the yield thereof. |
