摘要 |
PURPOSE: To prevent deterioration of gate breakdown strength due to cleaning before polysilicon deposition and to improve reliability by forming a buried contact hole after forming a first polysilicon film on a gate oxide film and by carrying out the precleaning thereafter. CONSTITUTION: A gate oxide film 22 is covered with a first polysilicon film 23 and it is precleaned in the state. Thereby, it is possible to prevent the gate oxide film 22 from being cut to deteriorate gate breakdown strength, unlike conventional methods, Furthermore, an inverted T-type MOS transistor can be formed readily by using a first polysilicon film and making it remain immediately below a spacer SiO2 film 33. Meanwhile, since a first polysilicon film piece 23A which is made electrically integral with a gate electrode exists on a low concentration source/drain layer in an inverted T-type gate MOS transistor, deterioration of conductance by hot carrier effect can be prevented. |