Ti-Al-C-N Gate Electrode Work Function Tuning
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Solution Overview
Problem
Conventional semiconductor device scaling techniques face challenges in finding suitable conducting materials for gate electrodes, particularly for PMOS regions in CMOS devices, and require new materials for applications like MIM structures, DRAM capacitors, and VNAND cells.
Innovation Solution
A method involving super cycles with transition metal and group 13 element sub cycles, including precursor pulses and reactant pulses, is used to form layers comprising transition metals and nitrogen, suitable for gate electrodes and other semiconductor applications, utilizing a reaction chamber with controlled gas flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional gate materials like titanium nitride are used, then the manufacturing process is simple, but the work function is insufficient for PMOS regions requiring higher work function values
Solution Approach 1:
The patent uses composite materials by combining titanium nitride with aluminum and carbon to form Ti-Al-C-N layers. This composite structure enables tuning of the work function to achieve higher values required for PMOS gate electrodes, while maintaining compatibility with existing semiconductor manufacturing processes.
Solution Approach 2:
The patent employs parameter changes by adjusting the composition ratios of titanium, aluminum, carbon, and nitrogen in the gate electrode material. By varying these compositional parameters, the work function can be precisely tuned to meet the specific requirements of different device regions, particularly achieving higher work functions for PMOS devices.
2Reliability
If new materials are developed for gate electrodes, then the work function can be tuned, but the manufacturing process complexity increases
Solution Approach 1:
The patent implements periodic action through cyclic deposition processes where precursors are introduced in alternating sequences. This periodic introduction of different precursors (titanium, aluminum, carbon, nitrogen) allows precise control over the composition and properties of the gate electrode material while maintaining a systematic and controllable manufacturing process.
Solution Approach 2:
The patent applies segmentation by dividing the deposition process into distinct sub-cycles, each introducing specific elements (titanium, aluminum, carbon, nitrogen) in controlled sequences. This segmented approach enables independent control of each element's incorporation, facilitating precise composition tuning while keeping the overall process manageable and scalable.
3Reliability
If complex multi-element layers are deposited, then the material properties can be optimized, but the deposition time increases
Solution Approach 1:
The patent maintains continuity of useful action by designing overlapping deposition cycles where precursor introduction and reaction steps are continuously performed without idle interruptions. This continuous process ensures that all four elements (titanium, aluminum, carbon, nitrogen) are incorporated efficiently, achieving optimized material properties while minimizing total deposition time.
Solution Approach 2:
The patent applies preliminary action by pre-heating precursors and maintaining reaction chamber conditions before actual deposition begins. This preliminary preparation ensures that when deposition starts, all elements are ready for immediate incorporation, reducing idle time and accelerating the overall deposition process while maintaining high material quality.
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 enables the formation of materials with tailored work functions and threshold voltage adjustments, enhancing the performance of semiconductor devices such as MOSFETs, MIM electrodes, and VNAND contacts.
Implementation Method 1
A transition metal sub cycle comprises a transition metal precursor pulse that comprises exposing the substrate to a transition metal precursor. The group 13 element sub cycle comprises a group 13 element precursor pulse that comprises exposing the substrate to a group 13 element precursor.
Data Source
AI summary
Disclosed are methods and systems for depositing layers comprising a transition metal and a group 13 element. The layers are formed onto a surface of a substrate. The deposition process may be a cyclical deposition process. Exemplary structures in which the layers may be incorporated include field effect transistors, VNAND cells, metal-insulator-metal (MIM) structures, and DRAM capacitors.