Semiconductor Multilayer Electrode Oxide Film Control
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Solution Overview
Problem
Conventional semiconductor devices with multilayer word line electrodes face challenges in maintaining uniform and precise oxide film thickness, leading to variations in threshold voltage and resistance, as well as issues with epitaxial growth, which complicates the formation of memory cells and protection diodes.
Innovation Solution
A semiconductor device with a silicon oxide film of uniform and optimal thickness is formed at the interface between the lower and upper electrodes of memory cells and between the substrate and diode electrodes, using ozone cleaning to control the film thickness and prevent epitaxial growth, thereby ensuring stable electrical connections and preventing abnormal growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal oxidation is used to form an oxide film, then the oxide film thickness can be controlled, but the thermal budget increases causing variation in element characteristics
Solution Approach 1:
The patent changes the method parameter from thermal oxidation to plasma oxidation, altering the physical-chemical process while maintaining the functional outcome of forming a controlled oxide film thickness without excessive thermal budget
Solution Approach 2:
The patent replaces the thermal field mechanism (thermal oxidation) with a plasma field mechanism (plasma oxidation), substituting one physical field for another to achieve the same oxide formation without the harmful thermal effects
2Productivity
If CVD is used to form an oxide film, then the number of process steps is reduced, but control of film thickness is difficult and minimum thickness degrades drive capability
Solution Approach 1:
The patent changes the deposition method from CVD to plasma oxidation, adjusting the process parameters to achieve precise thickness control while maintaining process efficiency
Solution Approach 2:
The patent uses plasma as a strong oxidizing environment to rapidly form the oxide film with precise thickness control, avoiding the minimum thickness limitation of CVD while maintaining drive capability
3Ease of manufacture
If natural oxidation is used to form oxide films, then the process is simple, but variations in oxide film thickness cause variations in threshold voltage and resistance
Solution Approach 1:
The patent replaces natural oxidation with plasma oxidation, substituting an uncontrolled thermal-diffusion process with a controlled plasma-based process that maintains simplicity while achieving uniform thickness
Solution Approach 2:
The patent uses plasma as a controlled strong oxidant to form uniform oxide films with precise thickness control, eliminating the thickness variations inherent in natural oxidation while keeping the process straightforward
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 solution ensures secure electrical connections between electrodes, inhibits abnormal epitaxial growth, and maintains the thermal budget and process steps, resulting in improved drive capability and reliability of memory cells and protection diodes.
Implementation Method 1
using ozone cleaning to control the film thickness and prevent epitaxial growth
Data Source
AI summary
The semiconductor device includes: memory cells each having a first multilayer electrode including a first lower electrode made of a first conductive film and a first upper electrode made of a second conductive film formed one on the other with a first interface film therebetween; and a diode having a diode electrode made of the second conductive film and a second interface film as a silicon oxide film formed at the interface between the diode electrode and a substrate. The first interface film has a thickness with which electrical connection between the lower electrode and the upper electrode is maintained, and the second interface film has a thickness with which epitaxial growth between the substrate and the diode electrode is inhibited.