Vertical Channel Structures Preventing Polysilicon Oxidation
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Solution Overview
Problem
Semiconductor memory devices with vertical channel structures face issues due to polysilicon oxidation or damage during the formation process, affecting the electrical characteristics of the devices.
Innovation Solution
The semiconductor device includes a substrate with a channel structure that extends through insulating and gate electrodes, featuring a stepped portion and multiple layers such as a tunnel insulating layer, charge storage layer, and blocking insulating layers, with a conductive channel contact layer and channel layer, and uses different materials for gate electrodes to improve reliability and prevent polysilicon oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vertical channel structures are formed by growing silicon in channel holes, then integration degree is increased, but polysilicon on side walls is oxidized or damaged during the process
Solution Approach 1:
A protective coating is formed on the side walls of channel holes before silicon growth, preventing oxidation and damage to polysilicon during subsequent processing steps. This preliminary protective action ensures the polysilicon maintains its electrical characteristics while still allowing the vertical channel structure to be formed for increased integration.
Solution Approach 2:
The protective coating acts as an intermediary layer between the polysilicon on channel hole side walls and the oxidizing environment during silicon growth. This intermediary layer prevents direct contact between polysilicon and oxidizing agents, preserving electrical characteristics while enabling the vertical channel formation process.
2Ease of manufacture
If polysilicon is used on channel hole side walls, then channel structure formation is enabled, but oxidation and damage occur during processing
Solution Approach 1:
The protective coating creates an inert environment for the polysilicon on channel hole side walls, shielding it from oxidizing conditions during silicon growth and subsequent processing. This allows the polysilicon to maintain its integrity and electrical properties while still serving its function in channel structure formation.
Solution Approach 2:
The protective coating is applied in advance before any oxidizing processes occur, establishing a protective barrier that prevents oxidation and damage to the polysilicon throughout the subsequent manufacturing steps.
Data Source
AI summary
Semiconductor devices are provided. The semiconductor devices may include a substrate, a ground selection gate electrode, and a channel structure. The channel structure may extend the ground selection gate electrode in a first direction perpendicular to a top surface of the substrate, and include a channel layer, a channel contact layer, and a stepped portion. The channel contact layer may contact the substrate and include a first width in a second direction perpendicular to the first direction. The channel layer may contact the channel contact layer, include a bottom surface between a bottom surface of the ground selection gate electrode and the top surface of the substrate in the first direction, and include a second width in the second direction different from the first width.