MIC Memory Channel With Superlattice Gettering for Impurity Control
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Solution Overview
Problem
Current semiconductor devices face limitations in achieving enhanced performance due to challenges in carrier mobility and material defects, despite existing advancements in strained materials and superlattice structures.
Innovation Solution
The implementation of a semiconductor device with a metal-induced crystallization (MIC) channel and a superlattice gettering layer, comprising stacked groups of semiconductor and non-semiconductor monolayers, which reduces charged impurity concentration and improves interface quality, thereby enhancing charge carrier mobility and providing piezoelectric, pyroelectric, and ferroelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If strained material layers are used to enhance carrier mobility, then device speed and performance are improved, but material defects and charged impurities increase causing performance degradation
Solution Approach 1:
A superlattice gettering layer is introduced as an intermediary structure between the strained material channel and the substrate. This layer acts as a mediator that captures and removes charged impurities and metal atoms, preventing them from degrading the channel performance while allowing the strained material to maintain its high mobility benefits
Solution Approach 2:
The superlattice gettering layer extracts and removes charged impurities, metal atoms, and other defects from the strained material channel region through its gettering effect. By taking out these harmful elements, the layer preserves the high carrier mobility while eliminating the reliability issues caused by impurities
2Speed
If superlattice structures are implemented to reduce alloy scattering, then carrier mobility is enhanced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The superlattice gettering layer is segmented into multiple thin alternating layers of different materials (e.g., SiGe and SiC) with thicknesses on the order of nanometers. This segmentation creates the superlattice structure that provides the desired electronic properties while confining the complexity to a localized region that does not affect the overall device architecture
Solution Approach 2:
The superlattice structure utilizes parameter changes in material composition and layer thickness to achieve the desired gettering effect and mobility enhancement. By carefully controlling the thickness ratios and material compositions, the structure optimizes carrier mobility while managing the complexity through precise parameter control rather than structural complexity
3Productivity
If metal-induced crystallization is used to form the channel, then manufacturing efficiency is improved, but metal particle contamination and defect formation increase
Solution Approach 1:
The superlattice gettering layer serves as an intermediary that facilitates the metal-induced crystallization process while simultaneously capturing the metal particles. It allows the metal to perform its useful function of inducing crystallization in the channel region while preventing the metal particles from becoming harmful contaminants that would degrade device reliability
Solution Approach 2:
The superlattice gettering layer converts the potentially harmful metal particles generated during metal-induced crystallization into a beneficial effect. By deliberately placing the gettering layer to capture these metal particles, the structure transforms what would be a source of defects into a mechanism for maintaining high device reliability while preserving the manufacturing efficiency benefits of MIC
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 configuration leads to improved charge carrier mobility, reduced scattering effects, and enhanced device performance, including higher mobility and reliability in NAND memory devices, while also acting as a barrier for dopant and material diffusion.
Implementation Method 1
a superlattice gettering layer between the substrate and the MIC channel... gettered metal particles from the MIC channel
Implementation Method 2
Si—Ge short period superlattice with higher mobility achieved by reducing alloy scattering in the superlattice
Implementation Method 3
The resulting biaxial strain in the upper silicon layer alters the carrier mobilities enabling higher speed and/or lower power devices
Data Source
AI summary
A semiconductor device may include a semiconductor substrate and a memory device on the semiconductor substrate including a metal induced crystallization (MIC) channel adjacent the semiconductor substrate, and a gate associated with the MIC channel. The semiconductor device may further include a superlattice gettering layer between the substrate and the MIC channel. The superlattice gettering layer may include a plurality of stacked groups of layers, with each group of layers comprising a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. The superlattice gettering layer may further include gettered metal particles from the MIC channel.