Capacitor Lower Electrode Surface Oxide Layer Contamination Prevention
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Solution Overview
Problem
Semiconductor capacitors with high aspect ratio electrodes are susceptible to surface contamination, which degrades their electrical characteristics.
Innovation Solution
A method of forming a semiconductor device that includes forming a lower electrode layer, a surface oxide layer, and a sacrificial layer, where the surface oxide layer is used to prevent contamination by being removed along with the sacrificial layer, thereby exposing the lower electrode and minimizing residue and pollutants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrodes are formed with high aspect ratio to meet high-integration density, then integration density is improved, but surface contamination susceptibility increases
Solution Approach 1:
A surface oxide layer is formed on the lower electrode layer before subsequent processing steps. This preliminary oxidation creates a protective barrier that prevents surface contamination during later etching and processing operations, allowing high aspect ratio electrodes to be formed without contamination issues
Solution Approach 2:
The surface oxide layer acts as an intermediary between the lower electrode layer and the contaminating environment. It serves as a sacrificial protective layer that can be selectively removed after serving its protective function, thereby preventing surface contamination while enabling high integration density
2Object-affected harmful factors
If a surface oxide layer is formed to prevent contamination, then surface contamination is prevented, but process complexity increases
Solution Approach 1:
The formation of the surface oxide layer is combined with existing oxidation processes in the fabrication sequence. By integrating the protective oxide formation into the standard process flow and using selective removal techniques, the solution prevents contamination without requiring entirely new process equipment or methods
Solution Approach 2:
The oxide layer is formed with specific thickness parameters and compositional characteristics that enable selective removal. By controlling the oxidation conditions and oxide layer properties, the process achieves contamination protection while maintaining compatibility with subsequent processing steps through parameter optimization
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 method effectively prevents surface contamination of the capacitor electrode, thereby maintaining the electrical integrity of the capacitor.
Implementation Method 1
The pre-flow process may use O3
Implementation Method 2
the oxidation process may use one or more of O2, O3, and H2O
Implementation Method 3
the deposition process may use one or more of O2, O3, H2O, a metal source gas, and a silicon source gas
Data Source
AI summary
A method of forming a semiconductor device includes forming a lower electrode layer on a substrate, forming a surface oxide layer on the lower electrode layer, partially removing the lower electrode layer to form a lower electrode, removing the surface oxide layer to expose the lower electrode, forming a capacitor dielectric layer on the lower electrode, and forming an upper electrode on the capacitor dielectric layer.