Backside Dielectric Liners for Nanosheet Contact Isolation
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Solution Overview
Problem
Conventional backside contact fabrication techniques for nanosheet transistor structures risk shorting with gate structures, posing a challenge in preventing electrical shorts.
Innovation Solution
The implementation of backside dielectric liners along the sidewalls of the top portion of the backside source drain contact in nanosheet transistor structures to prevent shorting between direct backside contacts and gate structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional backside contact fabrication techniques are used, then manufacturing simplicity is maintained, but electrical shorts between backside contacts and gate structures occur
Solution Approach 1:
A dielectric liner is introduced as an intermediary layer between the backside source/drain contact and the gate structure. This liner is disposed along the sidewalls of the backside contact and provides electrical insulation, preventing shorts while maintaining the backside contact configuration. The dielectric liner acts as a mediator that resolves the electrical insulation problem without requiring fundamental changes to the backside contact fabrication approach.
2Reliability
If dielectric liners are added to prevent shorting, then electrical insulation is improved, but manufacturing complexity increases
Solution Approach 1:
The dielectric liner is formed preliminarily before the gate structure is created. By depositing the dielectric liner on the sidewalls of the backside contact early in the fabrication sequence, the insulation barrier is established in advance. This preliminary action ensures that when the gate structure is subsequently formed, the electrical insulation is already in place, preventing shorts without requiring additional corrective steps later in the manufacturing process.
Data Source
AI summary
A semiconductor structure including a nanosheet transistor device including a backside source drain contact, where the backside source drain contact including a top portion, a middle portion, and a bottom portion, and a dielectric liner disposed along sidewalls of the top portion of the backside source drain contact.