Epitaxial Layer Growth Under Vapor Equilibrium for Dopant Activation
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Solution Overview
Problem
The variation in activation rate of dopant in epitaxial layers of semiconductor devices leads to increased on-resistance, threshold voltage variations, and potential breakdown due to current concentration at specific locations, necessitating an improvement in dopant activation rate and its uniformity.
Innovation Solution
A method involving the growth of epitaxial layers under an equilibrium vapor pressure environment, specifically the SiC—C or SiC—Si equilibrium vapor pressure, to achieve a higher activation rate of dopant, with a preferred activation rate of 33% or more, and incorporating a quantification step to measure and calculate the activation rate, ensuring uniform carrier concentration and reduced standard deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional epitaxial growth methods are used, then the manufacturing process is simple, but the activation rate of dopant is low and varies locally
Solution Approach 1:
The patent applies parameter changes by controlling the epitaxial growth process under specific equilibrium vapor pressure conditions (SiC-C or SiC-Si equilibrium). This involves precise control of temperature, pressure, and gas composition parameters to achieve high and uniform dopant activation rates. The growth is performed at controlled temperatures where the vapor pressure of silicon or carbon over silicon carbide maintains equilibrium, thereby improving manufacturing precision without excessive complexity increase.
2Reliability
If dopant concentration is increased to reduce on-resistance, then on-resistance decreases, but activation rate variation causes threshold voltage variation and current concentration
Solution Approach 1:
The patent applies local quality by ensuring uniform dopant activation across different locations in the epitaxial layer. The equilibrium vapor pressure growth method creates consistent growth conditions throughout the substrate, resulting in uniform activation rates (33% or more) across the entire layer. This uniformity prevents local variations in threshold voltage and avoids current concentration at specific locations, thereby improving reliability while maintaining overall energization capacity.
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 approach enhances the activation rate of dopants in epitaxial layers, reducing on-resistance and threshold voltage variations, while minimizing the risk of breakdown by achieving a high and uniform activation rate, thereby improving the performance and reliability of semiconductor devices.
Implementation Method 1
a growth step of growing the epitaxial layer on a bulk layer under an equilibrium vapor pressure environment
Data Source
AI summary
An object of the present invention is to provide a novel technique for improving an activation rate of dopant of an epitaxial layer. Another object of the present invention is to provide a novel technique for suppressing variation in activation rate of dopant in the epitaxial layer.The present invention is a method for improving the activation rate of dopant of an epitaxial layer 20, including a growth step S10 of growing the epitaxial layer 20 having the dopant on a bulk layer 10 under an equilibrium vapor pressure environment.