Metal Carbide Gate Layer Deposition for Threshold Voltage Control
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Solution Overview
Problem
Conventional device scaling techniques for semiconductor devices face challenges in finding suitable dielectric stacks that form an insulating barrier between the gate and channel of a field effect transistor, particularly in controlling the threshold voltage of transistors.
Innovation Solution
A method and system for depositing a metal carbide layer on a substrate using a cyclical deposition process, involving the use of metal alkyl, halogenated hydrocarbon, and a second metal precursor to form a metal carbide layer, which can be used in forming structures such as gate electrodes for CMOS transistors, controlling the threshold voltage through cyclical atomic layer deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional device scaling techniques are used, then device density and speed are improved, but finding suitable dielectric stacks to control threshold voltage becomes difficult
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric stack by introducing metal carbide materials with specific stoichiometries (MC, M2C, M3C2) and controlling their formation through cyclical deposition processes with controlled temperature and pressure parameters, enabling precise threshold voltage control
Solution Approach 2:
The patent employs composite dielectric stacks combining metal carbide layers with other dielectric materials, creating multi-layer structures that provide both the necessary electrical insulation and precise threshold voltage control for scaled devices
2Manufacturing precision
If metal carbide layer is deposited using cyclical deposition process, then threshold voltage control is improved, but deposition time increases
Solution Approach 1:
The patent employs a cyclical deposition process with repeated cycles of precursor introduction, heating, and purging steps that enable precise control of metal carbide layer formation, allowing threshold voltage tuning through the number and parameters of deposition cycles
Solution Approach 2:
The patent performs preliminary surface preparation and nucleation steps before the main deposition process, ensuring proper layer formation and reducing the number of subsequent cycles needed to achieve the desired threshold voltage control
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 the threshold voltage of field effect transistors, particularly for n-channel and p-channel MOSFETs, by inducing negative or positive flat band voltage shifts, enhancing the switching characteristics of CMOS devices.
Implementation Method 1
The cyclical deposition process can include one or more of an atomic layer deposition process and a cyclical chemical vapor deposition process
Implementation Method 2
The cyclical deposition process can include a thermal process—i.e., a process that does not use plasma-activated species
Implementation Method 3
In some cases, a precursor can be exposed to a plasma to form activated precursor species, e.g. radicals and/or ions
Data Source
AI summary
A method and system for depositing metal carbide on a substrate is provided. The method may include, providing a substrate in a reaction chamber, providing a first precursor comprising a metal alkyl provided with a first metal in the reaction chamber, providing a second precursor comprising a halogenated hydrocarbon in the reaction chamber, and providing a third precursor comprising a second metal different than the first metal in the reaction chamber. A metal carbide layer may be formed on the substrate.