TiN Work Function Control via Pulsed Gas Deposition
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Solution Overview
Problem
Existing semiconductor technologies face challenges in adjusting the work function of metal films used in MOSFETs, which is crucial for achieving desired performance in P-type and N-type transistors, as current methods lack the ability to precisely control the work function of metal films with the same element composition.
Innovation Solution
A method involving the sequential supply of halogen-based and organic source gases, along with nitrogen-containing gases, to form alternating layers of titanium nitride (TiN) films on a substrate, allowing for the adjustment of the work function by controlling the concentration of carbon, nitrogen, and chlorine in the TiN film through time-divided and pulsative gas supply processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single type of source gas is used to form metal film, then the manufacturing process is simple, but the work function cannot be adjusted
Solution Approach 1:
The patent segments the source gas supply into distinct phases: first supplying a halogen-based source gas to form a metal halide layer, then supplying an organic source gas to form a metal organic layer. This segmentation allows different gas types to contribute different elements (halogen and carbon respectively) to the metal film, enabling work function adjustment through controlled composition variation without requiring a completely different deposition process
Solution Approach 2:
The patent implements periodic action by alternating between halogen-based source gas supply and organic source gas supply in a time-divided manner. This periodic switching of gas types during deposition allows cyclic incorporation of different elements into the metal film layers, enabling precise control over the film's compositional gradient and corresponding work function adjustment
2Manufacturing precision
If halogen-based source gas is supplied continuously, then the metal film formation is efficient, but the atomic concentration control is poor
Solution Approach 1:
The patent applies dynamics by making the gas supply process adjustable and flexible rather than fixed. The halogen-based source gas and organic source gas are supplied in a time-divided and pulsative manner, allowing the supply conditions (timing, duration, pulse frequency) to be dynamically optimized. This enables precise control over the atomic concentration of halogen and carbon in the metal film while maintaining efficient film formation through optimized supply rhythms
Solution Approach 2:
The patent changes multiple parameters of the gas supply process including supply timing, pulse duration, frequency, and sequence. By varying these parameters, the atomic concentration of different elements (metal, halogen, carbon) in the deposited film can be precisely controlled. The time-divided and pulsative supply approach allows independent optimization of concentration control and deposition rate
3Adaptability or versatility
If alternating layers are formed by time-divided gas supply, then the work function is adjustable, but the manufacturing process becomes complex
Solution Approach 1:
The patent makes the deposition process multi-functional by using the same alternating gas supply mechanism to achieve multiple objectives: forming alternating layers with different compositions, controlling atomic concentration gradients, adjusting work function, and tailoring electrical properties. This universal approach eliminates the need for entirely different process steps for each function, simplifying the overall manufacturing while providing extensive property control
Solution Approach 2:
The patent creates composite metal film structures by combining layers formed from halogen-based source gas and organic source gas. These composite layers have different compositional characteristics (halogen-rich vs. carbon-rich regions) that together provide the desired work function and electrical properties. The composite structure approach allows property tailoring through composition design rather than requiring entirely different materials
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 approach enables precise control over the work function of the TiN film, improving the controllability of the atomic concentration and enhancing the performance of MOSFETs by allowing for the formation of metal films with tailored properties for specific transistor types.
Implementation Method 1
supplying a halogen-based source gas containing a first element to a substrate; supplying a reaction gas containing a second element to react with the first element to the substrate; forming a first layer containing the first element and the second element
Data Source
AI summary
A method of manufacturing a semiconductor device includes: (a) supplying a halogen-based source gas containing a first element to a substrate; (b) supplying a reaction gas containing a second element to react with the first element to the substrate; (c) forming a first layer containing the first element and the second element by time-dividing and performing (a) and (b) a predetermined number of times; (d) supplying an organic source gas containing the first element to the substrate; (e) supplying the reaction gas to the substrate; (f) forming a second layer containing the first element and the second element by time-dividing and performing (d) and (e) a predetermined number of times; and (g) forming a thin film containing the first element and the second element on the substrate by time-dividing and performing (c) and (f) a predetermined number of times.