Method of forming light doped drain electrode using side wall polymer grid structure

Abstract

In the method, a sidewall polymer is formed at two sides of grid and to use the grid and sidewall polymer as shielding to carry on a shallow ion implanting step after a gate oxide layer and polysilicon grid are formed on a substrate surface. A shallow in doping region can be formed in the substrate outside of the sidewall polymer by utilizing the width of this sidewall polymer so the shallow ion doping region can be diffused horizontally to the substrate under the sidewall polymer to form lightly doped drain structure in the following heat preparation process.

Description

【Technical field】 [0001] The present invention relates to a method for manufacturing a semiconductor component, in particular to a method for forming a lightly doped drain (LDD) using a sidewall polymer gate structure to accurately control channel length. 【Background technique】 [0002] When the size of the component is reduced, the channel length is also relatively reduced, but the problem caused by the shortened channel length will occur. This phenomenon is called the short channel effect (short channel effect). For conventional methods to solve the hot electron effect caused by short channels, please refer to Figure 1A As shown, a gate oxide layer 12 and a polysilicon gate 14 are formed on a substrate 10, and then using the polysilicon gate 14 as a shield, shallow ion implantation is performed on the substrate 10 to form a shallow ion doped region 16, This is used as a lightly doped drain (LDD). [0003] Then form a gate spacer (spacer) 18 on the substrate 10 on both s...

AI Technical Summary

Problems solved by technology

[0004] However, in the subsequent thermal process of the LDD 24, the ions of the LDD 24 often diffuse laterally due to heating, such as Figure 1C As shown, the diffusion to the position below the polysilicon gate 14 invades the channel region and shortens the length of the channel. This phenomenon will cause leakage current, punch through effect and shallow ion doping between the polysilicon gate and The short channel effect such as the parasitic capacitance (parasitic capacitor) in the miscellaneous area is particularly significant in the sub-micron process (less than 0.15μm process)

[0005] Therefore, in the face of higher and higher component integration and smaller and smaller process line widths, the lateral diffusion of LDD caused by the subsequent thermal process will not only shorten the channel distance, but will further form the short channel effect of the components. , which will affect the stability of components, will make it difficult to make smaller semiconductor components, and reduce the yield and electrical quality of components

Images