Novel method for conformal plasma immersed ion implantation assisted by atomic layer deposition

Abstract

Embodiments of the invention provide a novel apparatus and methods for forming a conformal doped layer on the surface of a substrate. A substrate is provided to a process chamber, and a layer of dopant source material is deposited by plasma deposition, atomic layer deposition, or plasma-assisted atomic layer deposition. The substrate is then subjected to thermal processing to activate and diffuse dopants into the substrate surface.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]Embodiments of the present invention generally relate to the fabrication of semiconductor devices and particularly to the formation of doped regions on a substrate by use of plasma implantation assisted by atomic layer deposition.[0003]2. Description of the Related Art[0004]In the semiconductor fabrication process, it is often necessary to impart impurities into a pure material. Called “doping,” this process invests the material with desirable properties, such as enhanced electrical conductivity. In many processes, it is advantageous to implant various atoms or ions into a semiconductor or semiconductor derivative substrate. For example, boron, phosphorus, and arsenic atoms or ions are routinely implanted into silicon substrates to create “doped” regions to serve as source and drain regions for solid state transistors. In some cases, the substrate is prepared prior to doping by “amorphizing” the region of the substrate ...

AI Technical Summary

Benefits of technology

[0012]Embodiments of the present invention further provide a method of processing a substrate having trenches, comprising disposing the substrate in a process chamber; providing a process gas mixture to the process chamber, wherein the process gas mixture comprises a dopant precursor; ionizing the dopant precursor into a plasma comprising dopant ions inside the process chamber; generating an electric field configured to maximize penetration of the dopant ions into the trenches of the substrate; and depositing the dopant ions conformally on the substrate.

Problems solved by technology

Increasing aspect ratios and shrinking devices pose challenges to dopant implantation processes.

High energy implantation may drive ions to the bottom of the trench, but generally will not achieve conformal implantation and may result in over-implantation in the bottom of the trench and in field areas as compared to side walls.

However, any such benefit is minimal, particularly for very high aspect ratio structures, because electric field lines driving the motion of ions are orthogonal to the surface.

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