Active Fin Structure With Stepped Field Insulation for Scaled ICs
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Solution Overview
Problem
In highly-scaled IC semiconductor devices, the challenge lies in enhancing the electrical characteristics such as short-channel effect and current driving capability, which is hindered by the limited design rules and height of active fins.
Innovation Solution
The integration of field insulating layers with a first and second subfield insulating layer configuration, where the surface of the first subfield insulating layer is lower than the second subfield insulating layer, allows for the formation of active fins that protrude from these layers, effectively increasing their height and improving electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the height of active fins is increased to improve electrical characteristics, then short-channel effect and current driving capability are improved, but the design rule constraints and manufacturing complexity increase
Solution Approach 1:
The field insulating layer is divided into two distinct sub-layers: a first subfield insulating layer and a second subfield insulating layer. This segmentation allows each layer to serve specific functions - the first layer provides baseline insulation while the second layer enables the active fins to protrude and achieve greater effective height, thereby improving electrical characteristics without requiring a complete redesign of the entire insulating structure.
Solution Approach 2:
The patent introduces vertical dimensionality variation by having the second subfield insulating layer extend higher than the first subfield insulating layer. This creates a stepped configuration where active fins can protrude from the higher second layer, effectively increasing the fin height in the vertical dimension without increasing the lateral footprint, thus avoiding design rule violations while improving current driving capability.
2Reliability
If the height of active fins is increased to improve current driving capability, then electrical performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The field insulating layers are formed with different heights before the active fin formation process. By pre-establishing the stepped insulating layer structure, the patent creates a built-in template that guides the subsequent fin formation. This preliminary action ensures that when active fins are grown or deposited, they automatically achieve the desired height variation without requiring complex real-time control during the fin fabrication process itself.
Solution Approach 2:
The patent changes the physical parameters of the field insulating layers by creating two sub-layers with different heights. This parameter variation (vertical height difference between first and second subfield insulating layers) directly translates to different effective fin heights, allowing precise control over electrical characteristics while simplifying the manufacturing process compared to attempting to control fin height through other means.
Data Source
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AI summary
An Integrated Circuit (IC) semiconductor device includes: field insulating layers buried in field trenches disposed apart from each other inside a substrate; active regions defined by the field insulating layers; and active fins disposed on the active regions and protruding from surfaces of the field insulating layers. The field insulating layers include a first subfield insulating layer and a second subfield insulating layer, and a surface of the first subfield insulating layer is disposed at a level lower than a level of a surface of the second subfield insulating layer.