Flash Memory Self-Aligned Contacts for Gate Leakage Isolation
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Solution Overview
Problem
Flash memory devices face reliability issues due to close proximity between gate and source/drain contacts, leading to leakage current, which reduces device reliability.
Innovation Solution
A flash memory device design with self-aligned contacts and liner structures that create a sufficient distance between contacts and the gate, using a method involving stack structures, dielectric columns, and sacrificial layers to form self-aligned contacts and maintain a larger process window, preventing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between gate and source/drain contact is reduced to increase device density, then productivity is improved, but reliability deteriorates due to leakage current
Solution Approach 1:
A liner structure (first liner structure and second liner structure) is introduced as an intermediary element between the self-aligned contact and the stack structure. This liner structure acts as a protective barrier during etching processes and provides electrical isolation, preventing direct interaction between the contact and gate that would cause leakage current. The liner structure enables closer spacing while maintaining reliability by mediating the interaction between adjacent components.
Solution Approach 2:
The liner structure is formed on the stack structure before the self-aligned contact etching process. This preliminary action protects the stack structure from damage during subsequent etching operations and pre-establishes the necessary electrical isolation. By preparing the protective liner in advance, the process enables safer and more precise formation of closely-spaced contacts without compromising gate integrity or causing leakage.
2Manufacturing precision
If a larger process window is achieved through self-aligned contact formation, then manufacturing precision is improved, but device complexity increases due to additional liner structures
Solution Approach 1:
The liner structure serves multiple functions simultaneously: it protects the stack structure during etching, provides electrical isolation between contact and gate, and defines the final contact geometry. By merging these multiple functions into a single structural element formed during the self-aligned contact process, the patent achieves high manufacturing precision without proportionally increasing device complexity. The liner structure is integrated into the existing process flow rather than added as a separate complex component.
Data Source
AI summary
Provided are a memory device and a method of manufacturing the same. The memory device includes: a stack structure; a first source/drain region and a second source/drain region located in a substrate beside the stack structure; a first self-aligned contact connected to the first source/drain region; a second self-aligned contact connected to the second source/drain region; a first liner structure located between the first self-aligned contact and a first sidewall of the stack structure; and a second liner structure located between the second self-aligned contact and a second sidewall of the stack structure. The first liner structure and the second liner structure are not connected and do not cover the stack structure.