TiPN Film Work Function Tuning via Sequential Gas Supply
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Solution Overview
Problem
Current semiconductor manufacturing techniques face challenges in adjusting the work function of conductive thin films, particularly in achieving a low work function value suitable for advanced transistor designs, as existing materials like titanium nitride films have work functions higher than required for optimal performance.
Innovation Solution
A method involving a substrate processing apparatus that forms a titanium phosphate nitride (TiPN) film by alternately supplying titanium tetrachloride (TiCl4), ammonia (NH3), and phosphine (PH3) gases to adjust the work function, utilizing the lower electronegativity of phosphorus to reduce the work function below that of titanium nitride (TiN) films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If titanium nitride (TiN) film is used as conductive thin film, then high reliability and low resistance are achieved, but work function value is higher than required for optimal transistor performance
Solution Approach 1:
The patent applies composite materials by forming a TiPN film that combines titanium, phosphorus, and nitrogen elements. The TiPN film integrates the beneficial properties of TiN (high reliability, low resistance) while incorporating phosphorus to reduce the work function, thus resolving the contradiction between maintaining reliability and reducing work function value
Solution Approach 2:
The patent changes the compositional parameters of the conductive film by introducing phosphorus into the TiN structure to create TiPN. By adjusting the phosphorus content and ratio of elements, the work function is tuned to lower values while preserving the electrical conductivity and reliability characteristics
2Ease of manufacture
If conventional conductive thin films are used, then manufacturing process is simple, but work function adjustment range is limited
Solution Approach 1:
The patent employs parameter changes by systematically varying the phosphorus content in TiPN films to achieve different work function values. The cyclic gas supply process allows precise control of P content, enabling continuous adjustment of work function while maintaining a relatively simple manufacturing process
Solution Approach 2:
The patent applies local quality by creating TiPN films with spatially varying phosphorus concentrations through controlled gas supply cycles. This enables different regions of the film to have different work function values, providing versatility for various transistor applications while maintaining ease of manufacture
3Reliability
If titanium nitride film is used, then low resistance is achieved, but power consumption cannot be optimized for advanced transistor designs
Solution Approach 1:
The patent changes the work function parameter of the conductive film by incorporating phosphorus into TiN to form TiPN. The reduced work function enables better band alignment and lower threshold voltage, optimizing power consumption while maintaining low resistance and high reliability through controlled compositional parameters
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 TiPN film achieves a lower work function compared to TiN films, enabling precise tuning of the work function for improved transistor performance and reduced power consumption, while maintaining the advantages of TiN films such as high reliability and low resistance.
Implementation Method 1
supplying a first reactive gas including the second element and reactive with the halogen-based source gas
Implementation Method 2
supplying a second reactive gas including the third element without mixing the second reactive gas with the first reactive gas, wherein the second reactive gas is reactive with the halogen-based source gas
Data Source
AI summary
A method of manufacturing a semiconductor device includes (a) providing a substrate and (b) forming a film including a first element, a second element and a third element in a same group as the second element on the substrate by performing a cycle a predetermined number of times, the cycle including: (b-1) supplying a halogen-based source gas including the first element to the substrate; (b-2) supplying a first reactive gas including the second element and reactive with the halogen-based source gas; and (b-3) supplying a second reactive gas including the third element without mixing the second reactive gas with the first reactive gas, wherein the second reactive gas is reactive with the halogen-based source gas and unreactive with the first reactive gas.