Curved Gate Electrode Profile for Leakage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing metal gate electrodes, particularly in forming gate trenches with complex profiles that affect device performance and reliability, such as increased leakage current and time-dependent dielectric breakdown.
Innovation Solution
A multi-step etching process is employed to form a wide middle gate trench with a gate electrode having a curved or inclined profile, which includes forming a dummy gate structure, spacers, and using specific etchants to create a gate trench with a unique profile that reduces leakage current and enhances device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional gate trench formation process is used, then the manufacturing process is simple, but the gate electrode profile is flat which increases leakage current and reduces device reliability
Solution Approach 1:
The etching process is divided into multiple sequential steps (first etching step, second etching step, third etching step) with different etchants and process parameters. Each step targets specific portions of the gate trench to achieve the desired curved profile, breaking down the complex task of forming a curved gate trench into manageable sequential operations that collectively produce the reliable device structure.
Solution Approach 2:
A dummy gate structure is formed before the actual gate trench etching process. This preliminary structure serves as a template and protective layer during the multi-step etching process, enabling precise formation of the curved gate trench profile while protecting underlying structures. The dummy gate is later removed and replaced with the final metal gate electrode.
2Productivity
If feature size is scaled down to increase functional density, then production efficiency and performance improve, but manufacturing complexity increases
Solution Approach 1:
Different regions of the gate trench receive different etching treatments through the multi-step process. The first etching step targets the upper portion with a first etchant, the second step addresses the middle portion with a second etchant, and the third step completes the lower portion with a third etchant. This localized approach enables precise control of the curved profile at each depth, achieving the required manufacturing precision for scaled devices while maintaining productivity.
Solution Approach 2:
The etching process parameters are systematically changed across multiple steps including etchant composition, temperature, pressure, and etching rate. These parameter variations enable selective removal of materials at different depths and rates, creating the curved gate trench profile necessary for scaled devices. The parameter changes allow the process to adapt to the reduced feature sizes while maintaining control and precision.
Data Source
AI summary
Provided is a semiconductor device including a gate electrode, source and drain regions, and a spacer. The gate electrode is located over a substrate, and an angle of a base corner of the gate electrode is greater than 90 degrees. The source and drain regions are located in the substrate at sides of the gate electrode. The spacer is located at a sidewall of the gate electrode.