Trench Gate Electrode Work Function Tuning for Channel Isolation
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Solution Overview
Problem
As semiconductor devices undergo high integration, the reduced unit cell area increases the likelihood of electron transport between adjacent cell channels, leading to potential transistor malfunctions such as data loss, which compromises electrical reliability.
Innovation Solution
A semiconductor device is designed with a substrate featuring a trench, where a gate electrode with a specific composition is placed. The gate electrode includes a gate conductor and a metal element, with an effective work function lower than that of the gate conductor, which is achieved by diffusing the metal element into the gate conductor. This configuration helps in reducing electron transport between adjacent channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high integration is implemented to reduce unit cell area, then device density and productivity are improved, but electrical reliability deteriorates due to increased electron transport between adjacent channels
Solution Approach 1:
The patent applies local quality by modifying the work function of the gate electrode specifically in regions adjacent to cell channels where electron transport is problematic. By creating a work function gradient with different metal element concentrations at different locations, the invention locally enhances electron barrier height where needed while maintaining overall device density from high integration.
Solution Approach 2:
The patent changes the work function parameter of the gate electrode by diffusing metal elements into the gate conductor. This parameter modification creates a higher energy barrier for electrons, preventing unwanted transport between adjacent channels while allowing the device to maintain high integration density.
2Reliability
If metal element is diffused into gate conductor to adjust work function, then electrical reliability is improved by raising electron transport barrier, but device complexity increases due to additional manufacturing steps
Solution Approach 1:
The patent applies preliminary action by forming the metal oxide film containing the metal element before forming the gate conductive layer. This sequence allows the metal element to be pre-positioned and then diffused into the gate conductor during subsequent processing, simplifying the overall manufacturing process compared to attempting to directly deposit complex metal alloys.
Solution Approach 2:
The patent uses a metal oxide film as an intermediary to introduce the metal element into the gate electrode structure. The metal oxide film serves as a precursor that releases the metal element during diffusion, acting as a mediator between the initial deposition step and the final gate electrode composition, thereby simplifying the manufacturing process.
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
The semiconductor device ensures enhanced electrical reliability by reducing electron transport between adjacent channels, thereby preventing malfunctions such as data loss. The effective work function adjustment effectively raises the barrier for electron transport, improving device reliability.
Implementation Method 1
The metal element may be diffused into the gate conductor
Implementation Method 2
an effective work function of the gate electrode is less than an effective work function of the gate conductor
Data Source
AI summary
A semiconductor device and a method of manufacturing the same are provided. The semiconductor device includes a substrate including a trench. The semiconductor device further includes a gate electrode disposed in the trench, and a gate insulating film disposed between the substrate and the gate electrode. The gate electrode includes a gate conductor and a metal element, and an effective work function of the gate electrode is less than an effective work function of the gate conductor.