3D Contact Plug Structure for Low-Resistance Source/Drain Contacts
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Solution Overview
Problem
Current semiconductor structures face poor electrical performance due to high contact resistance between contact plugs and source/drain doped layers, which is attributed to a small contact area between these components.
Innovation Solution
A method is developed to form a semiconductor structure by creating a trench and groove structure on the substrate, allowing for a larger contact area between the contact plug and the source/drain doped layer, which involves forming dielectric layers on the substrate, etching to expose the source/drain doped layer, and removing specific dielectric layers to enhance contact plug formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional contact plug structure is used, then the manufacturing process is simple, but the contact area between the contact plug and source/drain doped layer is small, resulting in high contact resistance
Solution Approach 1:
The contact plug transitions from a conventional planar contact to a three-dimensional structure that contacts the source/drain doped layer at multiple locations including the top surface and side walls, effectively adding vertical and lateral contact dimensions to reduce contact resistance
Solution Approach 2:
The contact plug is divided into multiple contact regions: a first contact region contacting the top surface of the source/drain doped layer, and a second contact region contacting the side wall of the source/drain doped layer, with each region contributing to the overall contact area and electrical performance
2Reliability
If the contact area between contact plug and source/drain doped layer is increased, then contact resistance is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
Dielectric layers are pre-formed around the source/drain doped layer before contact plug formation, creating a structured template that guides subsequent etching and contact plug deposition processes, thereby simplifying the overall manufacturing complexity despite the increased contact area
Solution Approach 2:
Dielectric layers serve as intermediary structures that define the contact regions and facilitate the formation of the multi-dimensional contact plug, acting as a mediator between the source/drain doped layer and the contact plug to achieve both large contact area and manufacturability
Data Source
AI summary
A semiconductor structure and a forming method thereof are provided, where one form of a forming method includes: providing a substrate, where the substrate includes a first region and a second region that are adjacent, stack structures are formed on the first region and the second region, and the stack structures of the first region and the second region and the substrate form a first opening; forming first dielectric layers on a bottom surface and side walls of the first opening, where a second opening is provided between the first dielectric layers; forming a second dielectric layer in the second opening; forming a source/drain doped layer; removing the first dielectric layer between the source/drain doped layer and the second dielectric layer, and forming a groove exposing a side wall, which is close to the second dielectric layer, of the source/drain doped layer; and forming a contact plug in the groove. In the embodiments of the present disclosure, the contact plug is in contact with a top surface of the source/drain doped layer as well as the side walls, which are close to the second dielectric layer and away from the second dielectric layer respectively, of the source/drain doped layer, so that a contact resistance between the contact plug and the source/drain doped layer is relatively small, thereby improving the electrical performance of the semiconductor structure.