3D Memory Channel Potential Control via GIDL Current
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Solution Overview
Problem
In three-dimensionally stacked memory devices, controlling the electric potential of the channel body is challenging due to the lack of direct connection to the substrate, which affects data erasure and writing operations.
Innovation Solution
A method is developed to form a U-shaped memory hole with a select gate and insulating layers, where a channel body is formed on the side wall of the hole, and a semiconductor film is buried in a space above the select gate, with a thinner insulating film thickness on the side walls to facilitate efficient data erasure and writing by utilizing GIDL current for boosting channel potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a three-dimensionally stacked memory structure is used to increase storage capacity, then memory density is improved, but controlling the electric potential of the channel body becomes difficult
Solution Approach 1:
The gate structure is segmented into multiple gates (first gate, second gate, third gate) positioned at different heights along the channel body. This segmentation allows independent control of electric potential at different regions of the channel, enabling effective potential control in the three-dimensional stacked memory structure while maintaining high memory density.
2Device complexity
If the channel body is not directly connected to the substrate, then three-dimensional stacking is achieved, but data erasure and writing operations are affected
Solution Approach 1:
A charge pump circuit is introduced as an intermediary mechanism to generate and supply high voltage to the gates. This charge pump enables effective data erasure and writing operations by providing the necessary high voltage potential through the floating gate structure, while maintaining the three-dimensional stacked configuration without direct substrate connection.
3Ease of operation
If a vertical transistor structure is added above the memory cell to control channel potential, then channel potential control is improved, but device complexity increases
Solution Approach 1:
The gate structure serves multiple functions: it acts as both the control gate for the vertical transistor and as the floating gate for charge storage. This multi-functionality allows channel potential control and data storage operations to be performed using the same structural elements, avoiding additional complexity from separate control mechanisms.
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 enables efficient data erasure and writing operations in three-dimensional memory devices by effectively controlling the channel potential, allowing for nonvolatile memory retention even when power is turned off.
Implementation Method 1
with a film thickness in a side wall portion surrounding the space thinner than a film thickness in a bottom portion sealing the hole... by utilizing GIDL current for boosting channel potential
Data Source
AI summary
According to one embodiment, a method is disclosed for manufacturing a semiconductor device. The second insulating film seals the hole near an interface of the insulating layer and the select gate. The second insulating film is provided on a side wall of the channel body with a space left in the hole above the select gate. The method can include burying a semiconductor film in the space, in addition, forming a conductive film in contact with the channel body.