Vertical Memory Cell Channel Composition for High-Density Deposition
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Solution Overview
Problem
Conventional vertical memory arrays face challenges in increasing memory density due to poor step coverage and inconsistent material deposition in high aspect ratio openings, leading to reduced quality and performance.
Innovation Solution
The use of heterogeneous channel materials with varying band gaps and compositions across the width of the channel, combined with advanced deposition techniques like ALD, to form barrier and channel materials that improve carrier confinement and mobility, and the formation of vertical memory cells with specific layer structures and materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the aspect ratio of openings is increased and width is decreased to increase memory density, then memory density is improved, but material deposition quality deteriorates with poor step coverage and inconsistent coverage
Solution Approach 1:
The patent applies local quality by using different semiconductor materials with different band gaps in different regions of the channel. Specifically, a first semiconductor material with a first band gap is used in a first region, and a second semiconductor material with a second band gap is used in a second region. This allows optimization of carrier confinement in specific regions without requiring uniform material properties throughout, thereby enabling high aspect ratio structures to be filled with adequate step coverage while maintaining device performance.
Solution Approach 2:
The patent employs composite materials by combining different semiconductor materials (e.g., SiGe and Si) within the same channel structure. The channel comprises a first semiconductor material in a first region and a second semiconductor material in a second region, creating a composite channel structure. This composite approach allows the device to benefit from the unique properties of each material (different band gaps) while achieving the geometric requirements for high density.
2Reliability
If conventional uniform semiconductor materials are used in vertical channels, then manufacturing is simpler, but carrier confinement and mobility are insufficient
Solution Approach 1:
The patent implements local quality by creating regions with different semiconductor materials tailored to specific functional requirements. The first semiconductor material with a first band gap is placed in a first region for optimized carrier confinement, while the second semiconductor material with a second band gap is placed in a second region for optimized mobility. This spatial variation in material properties enhances overall device performance without requiring complete structural redesign.
Solution Approach 2:
The patent applies parameter changes by varying the band gap parameter of the semiconductor material along the channel. By changing the material composition (e.g., Ge content in SiGe) to create different band gaps in different regions, the patent optimizes both carrier confinement and mobility. This parameter variation approach allows continuous optimization of device characteristics without fundamentally changing the device architecture.
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 memory density, improves pinch-off characteristics, reduces off-state leakage, and increases carrier mobility, resulting in more efficient and reliable memory devices.
Implementation Method 1
The channel material comprises a heterogeneous semiconductive material varying in composition across a width of the channel... At least one barrier material extends vertically along at least one sidewall of the channel material, the at least one barrier material comprising a heterogeneous semiconductive material varying in composition across a width of the at least one barrier material
Implementation Method 2
deposition of one or more material within the high aspect ratio openings decreases in quality... conformally deposited but, due to the high aspect ratio and narrow width, the materials deposited may suffer from poor step coverage
Data Source
AI summary
An electronic device comprises an array of memory cells comprising a channel material laterally proximate to tiers of alternating conductive materials and dielectric materials. The channel material comprises a heterogeneous semiconductive material varying in composition across a width thereof. Related electronic systems and methods are also disclosed.