3D Semiconductor Channel Grounding for Floating Body Suppression
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Solution Overview
Problem
The floating body effect in multi-layer stacked lateral transistors in 3D DRAM manufacturing leads to adverse consequences such as kink phenomenon, reduced drain breakdown voltage, and increased GIDL current, affecting device performance and reliability.
Innovation Solution
A three-dimensional semiconductor structure is formed with a stack of sacrificial and semiconductor layers, featuring parallel trenches and a grounded conductive plug to prevent charge accumulation in channel areas, thereby addressing the floating body effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-layer stacked lateral transistors are used to improve integration, then device integration is improved, but floating body effect occurs causing kink phenomenon, reduced drain breakdown voltage, and increased GIDL current
Solution Approach 1:
The patent extracts the harmful floating body effect by introducing a grounded conductive plug that removes accumulated charges from the channel area. The conductive plug is electrically connected to ground, effectively extracting the harmful charge accumulation that causes floating body effect, while preserving the multi-layer stacked transistor structure for high integration.
Solution Approach 2:
The grounded conductive plug acts as an intermediary element between the floating channel areas and ground. It provides a charge dissipation path without directly altering the transistor stack structure, mediating the charge accumulation problem while maintaining the high-integration architecture.
2Ease of manufacture
If channel areas are left floating to maintain simple structure, then manufacturing simplicity is maintained, but charge accumulation occurs leading to adverse effects
Solution Approach 1:
The harmful charge accumulation is extracted by introducing the grounded conductive plug. The plug provides a dedicated path for charge dissipation, removing the floating body effect while adding minimal structural complexity to the manufacturing process.
Solution Approach 2:
The grounding structure is applied locally at specific positions (source region and/or drain region) rather than throughout the entire device. This localized approach addresses charge accumulation where it occurs most severely while maintaining simplicity in other regions of the device.
Data Source
AI summary
A three-dimensional semiconductor structure and a method for forming the same are provided. The method includes the following operations. A stack structure in a source region and a drain region is etched to form a plurality of parallel first trenches extending in the first direction in the stack structure in the source region and the drain region, in which a plurality of semiconductor layers retained in the channel region serve as a plurality of channel body layers. The channel body layers extend in a second direction, and each includes a plurality of channel areas arranged in the second direction. A through via is formed in an end of the channel body layers in the second direction and penetrates the end. A conductive material is filled in the through via to form a grounded conductive plug.