Forming method of diffusion zone

Abstract

The invention relates to a forming method of a diffusion zone, comprising the following steps of: forming a pre-doping layer on the surface of a semiconductor substrate, wherein doping ions are contained in the pre-doping layer; forming a protecting layer on the pre-doping layer; annealing the semiconductor substrate; and diffusing the doping ions in the pre-doping layer into the semiconductor substrate. In the invention, by replacing the traditional mode of injecting ions to dope the diffusion zone with a furnace tube thermal diffusion technology, the damage to the surface of the semiconductor substrate by ionic bombardment is avoided, foreign ions are ensured to be more evenly distributed in the diffusion zone, a surface lattice structure is improved and a subsequent technology is benefited. In the process, the technological flow is slightly regulated, the complexity is not obviously increased, the production cost is not obviously increased, and the productivity is increased to a certain extent.

Description

technical field [0001] The invention relates to the field of semiconductor technology, in particular to a method for forming a diffusion region in a semiconductor device. Background technique [0002] In current semiconductor processes, it is often necessary to form various types of diffusion regions, such as source regions, drain regions, wells, buried layers, and the like. For RAM (Random Access Memory) devices, in the current 130nm process, the word line (word line) is usually served by an N-type buried layer in the semiconductor substrate. The so-called N-type buried layer is realized by N-type doping to the semiconductor substrate, and its function is to reduce the bulk resistance of the doped region. [0003] Technically, the doping of semiconductor substrates is mainly done by ion implantation. Ion implantation doping is to bombard ionized impurity ions to the surface of the substrate and enter the interior of the substrate after being accelerated by an electric fie...

AI Technical Summary

Problems solved by technology

Although the ion implantation technology plays an important role in the doping process, it also has some disadvantages: first, after the high-energy ions enter the semiconductor substrate, they will collide with the lattice atoms, causing many lattice atoms to be displaced, resulting in crystal grid damage; secondly, the existence of the implantation tilt angle makes the amount of ion implantation uneven at the trench structure; thirdly, because the energy of implanted ions is in a certain range, it is difficult to achieve too shallow or too deep implantation; in addition, the ion implanter The production is monolithic, and the production capacity is limited; moreover, the ion implanter is expensive, which increases the production cost

These methods all use follow-up remedial measures to repair the surface defects caused by ion implantation, but fail to fundamentally prevent the generation of implantation damage.

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