FinFET Multiple Fin Heights With BDI for Effective Width Tuning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current FinFET technology is limited by 'width quantization,' where transistors can only have discrete channel widths corresponding to single fin heights, restricting device design and performance.
Innovation Solution
The method involves co-integrating multiple fin heights with bottom dielectric isolations to achieve effective width tuning, allowing for transistors with arbitrarily varied effective channel widths on the same wafer substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If single fin height is used, then manufacturing process is simple, but effective channel width is restricted to discrete values
Solution Approach 1:
The fin structure is segmented into multiple height levels by introducing BDI regions at different depths. The substrate is divided into regions with different BDI heights, creating fins with discrete height segments that can be independently controlled to achieve various effective channel widths.
Solution Approach 2:
The patent transitions from a single-dimension (fin width) to a two-dimension approach by incorporating fin height as an additional degree of freedom. By controlling both fin width and fin height through BDI patterning, the effective channel area can be precisely tuned beyond what single-dimension scaling allows.
2Manufacturing precision
If multiple fin heights are integrated, then effective channel width can be tuned, but manufacturing process complexity increases
Solution Approach 1:
The BDI regions are formed preliminarily before fin formation through a sequence of deposition and etch-back steps. By pre-establishing the BDI height profile in the substrate, the subsequent fin formation process automatically inherits the height variation, eliminating the need for complex post-fin height adjustment procedures.
Solution Approach 2:
The patent controls the effective channel width by changing the BDI height parameter rather than modifying fin width. This parameter substitution allows precise width tuning while maintaining standard fin formation processes, as the BDI height can be controlled through deposition thickness and etch-back depth.
Data Source
AI summary
Embodiments of the present disclosure are directed to co-integrating multiple fin heights with bottom dielectric isolations for effective width tuning. In a non-limiting embodiment, a semiconductor structure includes a first shallow trench isolation (STI) region formed over a first portion of a substrate and a second STI region formed over a second portion of the substrate. A topmost surface of the second STI region is coplanar to a topmost surface of the first STI region. A first fin is formed in the first STI region and a second fin is formed in the second STI region. A topmost surface of the second fin is coplanar to a topmost surface of the first fin. A bottom dielectric isolation (BDI) region is positioned between the first fin and the substrate, thereby providing a first effective width and a second effective width for the first fin and second fin, respectively.