Carbon-Containing TiN Electrode for High Work Function
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Solution Overview
Problem
In semiconductor fabrication, the reduction in capacitor size to increase chip density leads to decreased capacitance, and using high permittivity dielectric layers results in high leakage current due to narrow band gaps, necessitating an electrode with a high work function.
Innovation Solution
A carbon-containing titanium nitride (TiN) layer with a carbon content of 3% to 50% is used as an electrode, formed through atomic layer deposition, which increases the work function and reduces leakage current by forming compounds like TiCN, TiSiCN, and TiAlCN.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a high permittivity dielectric layer is used to increase capacitance, then capacitance is improved, but leakage current increases due to narrow band gap
Solution Approach 1:
The patent changes the work function parameter of the electrode material by incorporating carbon into TiN, forming TixCyNz compounds. This parameter change in the electrode material allows the use of high permittivity dielectric layers while controlling leakage current through the modified electrode properties
Solution Approach 2:
The patent uses a composite electrode material consisting of titanium nitride combined with carbon elements (TixCyNz). This composite structure provides both the necessary electrical conductivity and the high work function required to interface with high permittivity dielectric layers, resolving the leakage current issue while maintaining capacitance
2Productivity
If capacitor size is reduced to increase chip density, then productivity is improved, but capacitance decreases
Solution Approach 1:
The patent changes the dielectric parameter by using high permittivity materials, which allows achieving required capacitance values in smaller capacitor volumes. This enables increased chip density while maintaining sufficient capacitance through the enhanced dielectric properties
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 carbon-containing TiN layer achieves a higher work function, increasing the Schottky barrier height and reducing leakage current while maintaining sufficient capacitance with a high permittivity dielectric layer.
Implementation Method 1
The TiN layer containing the carbon element may be formed through an atomic layer deposition (ALD) method that may repeat a unit cycle including a combination of flowing a titanium organic source and purging, flowing a silicon or aluminum source and a purging, and flowing plasma and purging
Implementation Method 2
The flowing of the plasma may be performed using a processing gas selected from the group consisting of N2, Ar, H2 and NH3
Data Source
AI summary
In a semiconductor device including a carbon-containing electrode and a method for fabricating the same, an electrode has a high work function due to a carbon-containing TiN layer contained therein. It is possible to provide a dielectric layer having a high permittivity and thus to reduce the leakage current by forming an electrode having a high work function. Also, sufficient capacitance of a capacitor can be secured by employing an electrode having a high work function and a dielectric layer having a high permittivity.