Three-Dimensional Memory Schottky Source Contact Formation via Mandrels
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Solution Overview
Problem
Existing three-dimensional memory devices face challenges in efficiently forming Schottky source contact structures, which are crucial for reliable operation and performance.
Innovation Solution
A method for forming a Schottky source contact structure in three-dimensional memory devices by creating a semiconductor structure with an alternating stack of insulating and conductive layers, including a memory opening fill structure with a vertical semiconductor channel and a source layer that provides a Schottky contact to the channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form Schottky source contact structures in three-dimensional memory devices, then device complexity is reduced, but manufacturing precision and reliability of the Schottky contact deteriorate
Solution Approach 1:
The patent applies preliminary action by forming a mandrel structure and depositing materials in predetermined sequences before finalizing the Schottky contact. The source contact layer is formed over a mandrel, and spacer materials are deposited and etched to create the final Schottky contact geometry. This staged approach ensures precise control of contact dimensions and positioning, achieving high manufacturing precision while managing structural complexity through systematic process design.
Solution Approach 2:
The patent uses intermediary structures including mandrels, spacer materials, and barrier layers that facilitate the formation of Schottky contacts. These intermediary elements serve as templates and protective layers during manufacturing, enabling precise pattern transfer and material deposition. The spacer materials act as intermediaries to define contact dimensions, while barrier layers prevent unwanted diffusion, collectively improving manufacturing precision without requiring direct complex patterning steps.
2Reliability
If Schottky source contact structures are formed with higher precision, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The patent segments the Schottky contact formation into distinct stages: forming the source contact layer over a mandrel, depositing spacer materials, selectively etching spacers, and forming barrier layers. Each segment performs a specific function and can be optimized independently. This segmentation enables precise control of contact reliability through controlled material deposition and etching, while managing overall process complexity by breaking down the manufacturing into manageable steps with clear process boundaries.
Solution Approach 2:
The patent utilizes parameter changes in material properties and deposition conditions to achieve reliable Schottky contacts. Different materials with specific electrical and physical properties are selected for different layers (e.g., conductive source contact layer, dielectric spacer, metallic barrier). By controlling deposition parameters such as thickness, composition ratios, and thermal processing conditions, the patent optimizes contact reliability. These parameter changes provide precise control over contact characteristics without requiring proportionally complex manufacturing processes.
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 proposed method enables the formation of reliable Schottky source contact structures, enhancing the performance and functionality of three-dimensional memory devices.
Implementation Method 1
forming a source layer on an exposed remaining end surface of the vertical semiconductor channel
Data Source
AI summary
A semiconductor structure includes an alternating stack of insulating layers and electrically conductive layers located on a semiconductor layer, a memory opening vertically extending through the alternating stack and the semiconductor layer, a memory opening fill structure located in the memory opening and containing a memory film and a vertical semiconductor channel, and a source layer that is formed at the bottom end of a vertical semiconductor channel. The source layer may comprise at least one metal that provides a Schottky contact to the vertical semiconductor channel.