Metal Silicate Dipole Layers for MOSFET Threshold Voltage Control
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Solution Overview
Problem
Conventional semiconductor device scaling techniques face challenges in controlling the threshold voltage of field-effect transistors, particularly due to difficulties in finding suitable gate stack materials and introducing additional oxygen content that increases equivalent oxide thickness and penalizes electrical performance.
Innovation Solution
The formation of ultra-thin metal silicate dipole layers with average thicknesses less than 0.1 nanometers, which are used to control the threshold voltage of MOSFETs, is achieved without the need for additional oxidizing agents, thereby avoiding increases in equivalent oxide thickness and maintaining electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional oxidizing agents are used to form metal silicate dipole layers, then the threshold voltage control is achieved, but the equivalent oxide thickness increases and electrical performance deteriorates
Solution Approach 1:
The patent extracts and removes the additional oxidizing agent step from the conventional metal silicate formation process. By using a single-source precursor that contains both metal and silicate components, the method eliminates the need for separate oxidation steps that would introduce additional oxygen and increase equivalent oxide thickness, thereby resolving the contradiction between threshold voltage control and electrical performance
Solution Approach 2:
The patent combines multiple functions into a single precursor material. The single-source precursor contains both the metal component and the silicate component in one molecule, allowing simultaneous deposition of both elements in a single atomic layer deposition cycle. This merging eliminates the need for separate oxidation steps and prevents additional oxygen incorporation, thus maintaining electrical performance while achieving threshold voltage control
2Length of moving object
If conventional gate stack materials are used, then device scaling is achieved, but threshold voltage control becomes difficult
Solution Approach 1:
The patent changes the material parameter by introducing metal silicate dipole layers with specific compositions (where x and y in MSi xOy can be independently controlled) into the gate stack. This allows continuous tuning of the effective work function and precise control of threshold voltage, enabling threshold voltage control in scaled devices where conventional materials fail
Solution Approach 2:
The patent uses composite metal silicate materials formed by combining metal atoms with silicate groups in a controlled ratio. This composite structure creates dipole layers with tunable electrical properties, providing the necessary threshold voltage control in scaled transistors while maintaining the benefits of device miniaturization
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 method effectively controls and adjusts the threshold voltage of field-effect transistors using ultra-thin metal silicate layers, improving the electrical performance of semiconductor devices while reducing the equivalent oxide thickness.
Implementation Method 1
forming a metal silicate threshold voltage shifting layer directly on the treated dielectric surface by contacting the treated dielectric surface with a precursor including a siloxide precursor or an organosilanol precursor
Data Source
AI summary
Methods for forming a metal silicate layer for controlling a threshold voltage of metal-oxide semiconductor field effect transistor (MOSFET) are disclosed. The methods include forming a metal silicate threshold adjusting layer on a substrate by contacting the substrate with a precursor comprising an organosilanol precursor or a siloxide precursor.