Vertical Transistor Doping Profile for Lower Leakage Current
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Solution Overview
Problem
Existing vertical transistors face challenges in reducing leakage current and enhancing contact resistance, particularly due to uniform doping profiles in channel layers, which limit their performance in high-density memory devices.
Innovation Solution
A vertical transistor design featuring different doping profiles in its upper and lower channel layers, with a gradual increase in metal component doping concentration from the intermediate region to the upper contact, and an abrupt increase near the lower contact, along with the use of insertion and barrier layers to manage oxygen scavenging and prevent oxidation, thereby reducing leakage current and contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform doping profile is used in the channel layer, then the manufacturing process is simple, but the leakage current cannot be effectively reduced
Solution Approach 1:
The patent applies local quality by creating different doping profiles in different regions of the channel layer. The first channel layer has a first doping profile while the second channel layer has a second doping profile, allowing each region to be optimized for its specific function - reducing leakage current while maintaining carrier transport efficiency.
Solution Approach 2:
The channel layer is segmented into multiple distinct layers (first channel layer and second channel layer) with different doping characteristics. This segmentation allows independent optimization of each layer's doping profile to address different electrical requirements along the vertical channel.
2Reliability
If oxide semiconductor is used as channel material, then electrical characteristics are improved, but oxygen scavenging and oxidation prevention are required
Solution Approach 1:
An oxygen scavenging layer is introduced as an intermediary between the oxide semiconductor channel layers and the surrounding environment. This layer actively scavenges oxygen and prevents oxidation of the oxide semiconductor, protecting the electrical characteristics while allowing the use of high-performance oxide materials.
Solution Approach 2:
The oxygen scavenging layer is positioned to preemptively prevent oxidation before it can occur in the oxide semiconductor channel layers. By placing the scavenging layer in contact with the oxide semiconductor, oxygen removal happens in advance, protecting the material's electrical properties.
Data Source
AI summary
Various embodiments of the present invention disclosure are directed to a vertical transistor having different doping profiles in its upper channel layer and lower channel layer for reducing leakage current while enhancing contact resistance and a method for manufacturing the vertical transistor. According to an embodiment of the present invention disclosure, a semiconductor device comprises a lower contact, a vertical channel layer on the lower contact, the vertical channel layer including a metal component and an oxygen component, and an upper contact on the vertical channel layer. The vertical channel layer has a gradual doping profile in which a doping concentration of the metal component is lowest in an intermediate region and gradually increases from the intermediate region to the upper contact.