Method for doping polycrystalline silicon layer

Abstract

The invention discloses a method for doping a polycrystalline silicon layer. The method comprises the following steps of: forming an N trap, an isolation region and a P trap on a substrate and depositing a gate oxide and the polycrystalline silicon layer on the surface of the substrate; doping the polycrystalline silicon layer above the P trap and the N trap by an ion injection process, wherein adoped ion is a P type element; and applying a mask to the polycrystalline silicon layer above the N trap and doping the polycrystalline silicon layer above the P trap by the ion injection process, wherein the doped ion is an N type element and the dosage of the N type element is more than that of the doped P type element. Due to the adoption of the method, a process flow for doping the polycrystalline silicon layer can be simplified.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for doping a polysilicon layer. Background technique [0002] With the wide application of electronic equipment, the manufacturing process of semiconductors has been developed rapidly. In the manufacturing process of semiconductors, a method of doping a polysilicon layer is involved. Figure 1 ~ Figure 3 It is a cross-sectional structure diagram of the process of doping the polysilicon layer in the prior art. This method of doping the polysilicon layer is for the double well structure. After the N well and the P well are formed on the substrate, the N well The polysilicon layer is doped with P-type elements to form P-type transistors, and the polysilicon layer above the P well is doped with N-type elements to form N-type transistors, such as Figure 1 ~ Figure 3 As shown, the method includes the following steps: [0003] Step one, see figure 1 1. A substrate ...

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Problems solved by technology

It can be seen that this method involves two mask application processes and one mask removal process, which makes the process flow of polysilicon layer doping more complicated.

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