Boron Gettering Substrate for Semiconductor Impurity Control
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Solution Overview
Problem
The manufacturing process of semiconductor devices with increasingly finer structures is limited by a thermal budget, causing degradation in the size and density of precipitation nuclei used for gettering metallic impurities, and existing methods like carbon doping require high-temperature heat treatments that are not compatible with these constraints.
Innovation Solution
A semiconductor device is fabricated using a substrate with a supersaturated boron impurity layer formed by ion implantation, creating a B12 cluster that acts as a gettering site for metallic impurities, allowing effective impurity gettering even within a limited thermal budget.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon doping is used to form precipitation nuclei for gettering metallic impurities, then the gettering amount of metallic impurities is improved, but high-temperature heat treatments are required which are not compatible with limited thermal budget in modern semiconductor manufacturing
Solution Approach 1:
The invention changes the chemical composition parameter by doping with boron instead of carbon, and changes the formation mechanism parameter by using ion implantation instead of thermal diffusion. This allows precipitation nuclei to form at lower temperatures (below 1000°C) while maintaining effective gettering capability for metallic impurities
Solution Approach 2:
The invention replaces the thermal diffusion mechanism with ion implantation mechanism. By implanting boron ions directly into the silicon substrate, precipitation nuclei are formed without requiring prolonged high-temperature heat treatment, thus resolving the contradiction between gettering effectiveness and thermal budget constraints
2Temperature
If short-time heat treatment using RTA is used to meet thermal budget limits, then the thermal budget constraint is satisfied, but the size and density of precipitation nuclei are degraded
Solution Approach 1:
The invention performs preliminary action by implanting boron ions during the manufacturing process to directly create precipitation nuclei. This preliminary formation of nuclei eliminates the need for subsequent high-temperature heat treatment to grow them, thus satisfying thermal budget limits while maintaining nuclei size and density
Solution Approach 2:
The invention replaces thermal growth mechanism with ion implantation mechanism for forming precipitation nuclei. This substitution allows nuclei to be formed directly at lower temperatures with controlled size and density, avoiding the degradation that occurs with limited thermal budget heat treatments
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
The B12 cluster induces a bivalent electron deficiency state, effectively getting metallic impurities and improving the reliability of semiconductor devices by forming a stable gettering site that can be integrated into the manufacturing process without significant thermal influence on other regions.
Implementation Method 1
a supersaturated boron impurity layer formed by ion implantation
Implementation Method 2
effectively getting metallic impurities and improving the reliability of semiconductor devices
Data Source
AI summary
According to an embodiment, a semiconductor device includes a substrate provided with a first region including an active element, the substrate including a second region containing boron with a density of 2×1020 cm−3 or more on a surface excluding the first region.