| 摘要 |
A method for forming a gate of a semiconductor device is provided to restrain the generation of a gate depletion and to improve the reliability and yield of the device by increasing the dose of a gate polysilicon layer using two-step ion implantations. A gate oxide layer(4) is formed on a silicon substrate(1) having a P-well(3a) and an N-well(3b). A undoped polysilicon layer(5) is formed on the gate oxide layer. An N type ion implantation is performed on the undoped polysilicon layer corresponding to the P-well. A P type ion implantation is performed on the resultant polysilicon layer corresponding to the N-well. An annealing process is performed on the resultant structure. Then, the polysilicon layer and the gate oxide layer are selectively etched. The P type and N type ion implantations are performed by using two-step processing, respectively.
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