Gate Structure with Segmented End Portions for Semiconductor Devices
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Solution Overview
Problem
The challenge in forming reliable semiconductor devices with increasingly smaller feature sizes is the tendency of gates to collapse during ion implantation and cleaning processes due to surface tension and short gate lengths, making it difficult to maintain structural integrity and achieve desired channel lengths.
Innovation Solution
A semiconductor device formation process involving a gate with an intermediate portion and two end portions, where the intermediate portion is shortened through etching while the end portions remain longer, preventing gate collapse and allowing for a short channel length, using a mask layer and etching processes to maintain gate height and structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If gate length is reduced to achieve smaller feature sizes, then scaling-down process benefits are improved, but gate structural integrity deteriorates causing gate collapse
Solution Approach 1:
The gate is divided into two distinct portions: a first portion extending over the active region with a first length, and a second portion extending over the isolation structure with a second length longer than the first length. This segmentation allows the gate to have different length characteristics in different regions, providing both short channel length for device performance and longer support portions for structural integrity during ion implantation and cleaning processes
Solution Approach 2:
Different portions of the gate are given different local characteristics. The first portion over the active region has a shorter length optimized for channel performance, while the second portion over the isolation structure has a longer length providing structural support. This local differentiation resolves the contradiction by allowing each region to serve its specific function without compromising the other
2Productivity
If feature size is reduced to increase functional density, then production efficiency is improved, but fabrication process difficulty increases
Solution Approach 1:
By segmenting the gate into first and second portions with different lengths, the structure maintains manufacturability at small feature sizes. The longer second portion provides structural support that prevents collapse during fabrication, making it easier to manufacture small-scale devices without sacrificing production efficiency
Solution Approach 2:
The longer second portion of the gate extending over the isolation structure acts as a pre-positioned structural support that cushions against the harmful effects of surface tension during ion implantation and cleaning processes. This beforehand cushioning prevents gate collapse before it can occur, enabling reliable fabrication at reduced feature sizes
3Length of moving object
If gate length is reduced to achieve short channel length, then device scaling is improved, but gate collapse during ion implantation increases
Solution Approach 1:
The gate is segmented into a first portion providing the short channel length for device scaling and a second portion providing structural stability. This segmentation allows the channel region to be short for performance while the support region remains long for stability during ion implantation and cleaning processes
Solution Approach 2:
The second portion of the gate extending over the isolation structure acts as an intermediary support element that mediates between the short channel portion and the external processing environment. It provides structural reinforcement that prevents collapse during ion implantation and cleaning while not interfering with the electrical function of the short channel region
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents gate collapse and achieves a short channel length, ensuring the reliability and integrity of semiconductor devices even at nanoscale dimensions, enhancing manufacturing efficiency and device performance.
Implementation Method 1
performing an etching process to decrease a first gate length of the intermediate portion
Implementation Method 2
the tendency of gates to collapse during ion implantation and cleaning processes
Implementation Method 3
the tendency of gates to collapse during ion implantation and cleaning processes due to surface tension
Data Source
AI summary
Embodiments of mechanisms for forming a semiconductor device are provided. The semiconductor device includes a semiconductor substrate. The semiconductor device also includes an isolation structure in the semiconductor substrate and surrounding an active region of the semiconductor substrate. The semiconductor device includes a gate over the semiconductor substrate. The gate has an intermediate portion over the active region and two end portions connected to the intermediate portion. Each of the end portions has a first gate length longer than a second gate length of the intermediate portion and is located over the isolation structure.