Thinned High-K Dielectric for FET Reliability
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Solution Overview
Problem
Current technologies face challenges in adjusting dielectric thickness to improve the reliability of n-channel and p-channel field effect transistors, as thinner dielectric materials enhance positive bias temperature instability for nFETs while thicker materials improve negative bias temperature instability for pFETs, but achieving this balance is difficult.
Innovation Solution
The method involves depositing a high-k dielectric material on both nFET and pFET sides of a substrate and using titanium nitride (TiN) with a TiCl4 precursor to selectively etch the high-k dielectric, allowing for controlled thinning of the dielectric material, specifically HfO2, to achieve the desired thickness for improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dielectric thickness is adjusted to improve reliability, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The titanium nitride layer serves a dual function: it acts as a gate electrode material and simultaneously provides atomic-level etching of the high-k dielectric material through its deposition process. This self-service mechanism enables precise thickness control without requiring separate etching steps, improving manufacturing precision while minimizing the increase in device complexity
Solution Approach 2:
The patent utilizes parameter changes in the deposition process, specifically depositing titanium nitride at temperatures between 300-450°C using TiCl4 precursor, which enables atomic-level etching of the high-k dielectric. This parameter optimization allows precise control of dielectric thickness with atomic-level precision, achieving high manufacturing precision without significantly complicating the manufacturing process
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 atomic-level control over dielectric thinning, enhancing the reliability of scaled devices by allowing for thicker HfO2 for pFETs and thinner HfO2 for nFETs, thereby improving negative and positive bias temperature instability respectively.
Implementation Method 1
depositing titanium nitride (TiN) with a precursor of TiCl4 directly on the high-k dielectric material
Implementation Method 2
simultaneously etching the high-k dielectric... The high-k dielectric material of at least one of the nFET device and the pFET device includes Cl
Data Source
AI summary
The disclosure relates to semiconductor structures and, more particularly, to structures with thinned dielectric material and methods of manufacture. The method includes depositing a high-k dielectric on a substrate. The method further includes depositing a titanium nitride film directly on the high-k while simultaneously etching the high-k dielectric.