PIP Capacitor Fabrication via Simultaneous Oxidation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for fabricating Polysilicon-Insulator-Polysilicon (PIP) capacitors face challenges in securing uniformity of transistors, formation of silicide, and maintaining the relative thickness of polysilicon electrodes, while also minimizing washing and furnace steps to maximize productivity.
Innovation Solution
A method involving the simultaneous formation of gate oxide and insulating oxide films with increasing doping concentration of the lower polysilicon electrode, allowing for the formation of upper polysilicon electrodes and gate electrodes at the same time, which reduces the need for separate washing and furnace steps and enhances uniformity and silicide formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate polysilicon oxidizing step and gate oxide film forming step are performed, then oxide film thickness can be controlled, but transistor uniformity deteriorates and productivity decreases
Solution Approach 1:
The patent combines the polysilicon oxidizing step and gate oxide film forming step into a single simultaneous oxidizing process. The oxidizing conditions are controlled so that oxide films grow on both the polysilicon electrode and the silicon substrate at the same time, eliminating the need for separate processing steps while maintaining thickness control.
Solution Approach 2:
The single oxidizing step serves multiple functions: it forms the insulating oxide film on the polysilicon electrode and simultaneously forms the gate oxide film on the silicon substrate. This multi-functional approach reduces the total number of processing steps while achieving both objectives.
2Manufacturing precision
If separate polysilicon oxidizing step and gate oxide film forming step are performed, then oxide film thickness can be controlled, but transistor uniformity deteriorates
Solution Approach 1:
The patent combines the polysilicon oxidizing step and gate oxide film forming step into a single simultaneous oxidizing process. The oxidizing conditions are controlled so that oxide films grow on both the polysilicon electrode and the silicon substrate at the same time, eliminating the need for separate processing steps while maintaining thickness control.
Solution Approach 2:
The patent performs preliminary doping of the polysilicon electrode with phosphorus before the simultaneous oxidizing step. This preliminary action ensures that the polysilicon electrode has the appropriate electrical properties and facilitates uniform oxide growth during the combined process, which in turn ensures uniform transistor characteristics.
3Manufacturing precision
If multiple washing and furnace steps are performed, then fabrication precision can be maintained, but productivity decreases
Solution Approach 1:
The patent merges multiple separate processing steps (polysilicon oxidation, gate oxide formation, and doping) into a single simultaneous oxidizing process with preliminary doping. This consolidation reduces the total number of washing and furnace steps required while maintaining the necessary fabrication precision through controlled oxidizing conditions.
4Reliability
If thick nitride is used in ONO structure, then insulating performance is improved, but etching completeness deteriorates and silicide formation fails
Solution Approach 1:
The patent extracts the nitride layer from the insulating structure, replacing the conventional ONO (oxide-nitride-oxide) structure with a simplified oxide-only structure. By removing the nitride layer entirely, the patent eliminates the etching completeness problem and silicide formation failure while maintaining adequate insulating performance through the oxide films alone.
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 ensures substantial uniformity of transistors, secure formation of silicide, and maintains the thickness of polysilicon electrodes, while minimizing the number of washing and furnace steps, thereby maximizing productivity in PIP capacitor fabrication.
Implementation Method 1
performing an oxidizing step to form a first oxide film on and/or over tops and/or side walls of a lower polysilicon electrode
Implementation Method 2
to grow a second oxide film on and/or over an active region of a silicon substrate
Data Source
AI summary
A PIP capacitor and methods thereof. A method of fabricating a PIP capacitor may include forming a field oxide film over a silicon substrate to define a device isolating region and/or an active region. A method of fabricating a PIP capacitor may include forming a lower polysilicon electrode having doped impurities on and/or over an field oxide film. A method of fabricating a PIP capacitor may include performing an oxidizing step to form a first oxide film over a polysilicon and/or a second oxide film on and/or over an active region. A method of fabricating a PIP capacitor may include forming an upper polysilicon electrode on and/or over a region of a first oxide film and forming a gate electrode on and/or over a second oxide film at substantially the same time. A method of fabricating a PIP capacitor may include forming a polysilicon resistor. A PIP capacitor is disclosed.