Stacked Metal Nitride Gate Electrode Work Function Tuning
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Solution Overview
Problem
Existing semiconductor manufacturing techniques face challenges in adjusting the work function of metal films, which is crucial for optimizing transistor performance, particularly for reducing power consumption in NMOS transistors, as the work function varies with device requirements.
Innovation Solution
A method involving the formation of a stacked metal nitride film by alternately supplying a first metal source containing iodine and a nitrogen-containing source, and a second metal source containing chlorine, to create a film with adjustable work function, utilizing a substrate processing apparatus that controls gas supply and deposition processes to achieve the desired film properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single metal film is used as the gate electrode, then the manufacturing process is simple, but the work function cannot be adjusted to meet different device performance requirements
Solution Approach 1:
The gate electrode is divided into multiple metal nitride films (first metal nitride film and second metal nitride film) with different work functions. By segmenting the single film into stacked layers, each layer can contribute differently to the overall work function, enabling adjustment of the effective work function through varying thickness ratios while maintaining manufacturing simplicity.
Solution Approach 2:
The patent uses a composite structure of multiple metal nitride films with different chemical compositions (different metal elements and halogen elements). This composite approach allows the gate electrode to achieve a tailored work function by combining materials with distinct properties, solving the adaptability issue without requiring completely different material systems.
2Manufacturing precision
If the work function is adjusted by changing metal film composition, then device performance can be optimized, but the manufacturing precision required increases
Solution Approach 1:
The patent adjusts the work function by changing the thickness parameters of each metal nitride film layer rather than requiring precise control of metal content within a single film. This parameter change approach (controlling thickness ratios) simplifies the manufacturing process while achieving precise work function control, as thickness control is more straightforward than compositional control in deposition processes.
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 allows for precise adjustment of the work function of the metal film, enhancing the electrical characteristics of the transistor, such as reducing resistivity and improving film thickness and roughness, thereby optimizing device performance.
Implementation Method 1
forming a stacked metal nitride film including a first metal nitride film and a second metal nitride film on a substrate by alternately performing steps (a) and (b) a plurality of times, wherein the step (a) includes alternately supplying: a first metal source containing a first halogen element and a metal element; and a nitrogen-containing source to the substrate
Data Source
AI summary
Provided is a method of manufacturing a semiconductor device, including: forming a stacked metal nitride film including a first metal nitride film and a second metal nitride film on a substrate by alternately performing steps (a) and (b) a plurality of times, wherein the step (a) includes alternately supplying: a first metal source containing a first halogen element and a metal element; and a nitrogen-containing source to the substrate a plurality of times to form the first metal nitride film, and the step (b) includes alternately supplying: a second metal source containing a second halogen element different from the first halogen element and the metal element; and the nitrogen-containing source to the substrate a plurality of times to form the second metal nitride film.