Metal Gate Transistors with Transition-Metal Oxycarbide Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The scaling down of semiconductor integrated circuits has led to increased complexity and power dissipation, necessitating the development of low power dissipation devices like CMOS with metal gate electrodes, where existing techniques face challenges in thermal stability and process complexity between gate-first and gate-last processes.
Innovation Solution
The implementation of a transition-metal oxycarbide containing layer with a transition metal atomic percentage of 40% or more, which provides thermal stability and modulates the work function of transistors, allowing for the formation of CMOS field effect transistors with improved resistivity and thermal stability under rapid thermal anneal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a gate-first process is used to form metal gate electrode, then the process is simpler than gate-last process, but the metal gate electrode is not thermally stable during high-temperature thermal process
Solution Approach 1:
The patent forms the metal gate electrode before source/drain region formation (gate-first approach), but applies preliminary protective actions by using a specific metal composition (40 at.% or more of a particular metal element) that is pre-engineered to be thermally stable. This preliminary design of the metal composition prevents thermal degradation during subsequent high-temperature annealing processes, resolving the contradiction between process simplicity and thermal stability.
2Reliability
If a gate-last process is used to form metal gate electrode, then thermal stability is improved, but the process becomes more complicated
Solution Approach 1:
The patent changes the compositional parameters of the metal gate electrode by specifying that it contains 40 at.% or more of a particular metal element. This parameter change enables the metal gate to achieve thermal stability comparable to gate-last processes while maintaining the simpler gate-first process flow, thus reducing process complexity while preserving thermal stability.
3Productivity
If feature size is decreased to increase functional density, then production efficiency is improved, but power dissipation increases
Solution Approach 1:
The patent changes the material composition parameters of the metal gate electrode, specifying that it contains 40 at.% or more of a particular metal element with suitable work function. This compositional change enables better control of threshold voltage and reduced leakage current in scaled devices, thereby reducing power dissipation while maintaining the small feature sizes needed for high production efficiency.
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 solution enables the formation of thermally stable CMOS transistors with desired work functions for both NMOS and PMOS transistors, addressing the challenges of power dissipation and process complexity while maintaining efficiency in transistor manufacturing.
Implementation Method 1
the transition-metal (M) has an atomic percentage of about 40 at. % or more to modulate a work function of the transistor device
Implementation Method 2
improved device performance under rapid thermal anneal conditions
Data Source
AI summary
A semiconductor device includes at least one first gate dielectric layer over a substrate. A first transition-metal oxycarbide (MCxOy) containing layer is formed over the at least one first gate dielectric layer, wherein the transition-metal (M) has an atomic percentage of about 40 at. % or more. A first gate is formed over the first transition-metal oxycarbide containing layer. At least one first doped region is formed within the substrate and adjacent to a sidewall of the first gate.