Ultra-Shallow Junction Formation Using a Removable Epitaxial Layer
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Solution Overview
Problem
Current semiconductor technologies face challenges in achieving low-energy and low-dose ultra-shallow junction implantation, particularly for channel and Light Dopant Drain (LDD) implantations, due to limitations in process conditions and beam attenuation during ion implantation.
Innovation Solution
A method involving the formation of an epitaxial layer on a semiconductor substrate, followed by dopant implantation and subsequent removal of the epitaxial layer to create an ultra-shallow junction, allowing for a high-energy and high-dose implantation to achieve a low-energy and low-dose effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ion implantation methods are used, then high-energy and high-dose implantation can be achieved, but low-energy and low-dose implantation effect cannot be obtained
Solution Approach 1:
An epitaxial layer is introduced as an intermediary between the ion source and the semiconductor substrate. This layer allows high-energy ions to be implanted without directly damaging the substrate, and subsequent removal of the epitaxial layer leaves behind the desired dopant profile in the substrate, achieving low-energy equivalent effect with high-energy implantation
2Quantity of substance
If high-energy ion implantation is used, then sufficient dopant dose can be delivered, but the junction depth becomes too deep
Solution Approach 1:
The semiconductor structure is segmented into an epitaxial layer and a substrate. The epitaxial layer serves as a temporary host for the dopant during implantation, allowing high-dose implantation. After dopant incorporation, the epitaxial layer is removed, leaving the dopant in the substrate at the desired shallow depth, thus separating the implantation process from the final junction location
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the achievement of a low-energy and low-dose implantation effect, addressing the difficulties in related technologies by controlling the dopant dose and using high-energy and high-dose implantation processes.
Implementation Method 1
providing a dopant and implanting the dopant into the epitaxial layer and a part of the semiconductor substrate
Data Source
AI summary
A method for forming an ultra-shallow junction includes the following operations: providing a semiconductor substrate, forming an epitaxial layer on the semiconductor substrate, providing a dopant and implanting the dopant into the epitaxial layer and a part of the semiconductor substrate, and removing the epitaxial layer, to form the ultra-shallow junction.