Oxide Semiconductor Evaluation via MOS Capacitor C-V Analysis
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Solution Overview
Problem
The evaluation of oxide semiconductors is unclear, lacking established methods, and hydrogen in these semiconductors induces unwanted carriers, making it difficult to determine optimal manufacturing conditions for removing hydrogen and achieving high-performance semiconductor devices.
Innovation Solution
A method involving the formation of MOS capacitors to measure carrier density through C-V characteristics, allowing for the evaluation of hydrogen concentration and determination of optimal processing conditions such as heating and film formation parameters, and providing feedback for improving semiconductor device manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hydrogen is present in oxide semiconductor, then carrier density increases, but device performance deteriorates due to unwanted carriers
Solution Approach 1:
The patent converts the harmful effect of hydrogen (which increases carrier density) into a beneficial evaluation tool. By measuring carrier density through C-V characteristics, the method indirectly detects hydrogen concentration and uses this information to optimize processing conditions, thereby transforming a detrimental factor into a diagnostic advantage for improving device performance
Solution Approach 2:
The patent implements a feedback mechanism where carrier density measurements from C-V characteristics are used to evaluate and adjust manufacturing processes. The measured carrier density provides feedback on hydrogen concentration, which then guides optimization of heat treatment and film formation conditions to achieve desired device performance
2Object-affected harmful factors
If heat treatment is performed to remove hydrogen, then hydrogen concentration decreases, but additional processing time and complexity are required
Solution Approach 1:
The patent applies preliminary action by incorporating heat treatment steps during the film formation process itself, rather than requiring separate post-processing steps. The film formation conditions are optimized to include heat treatment parameters that remove hydrogen concurrently with oxide semiconductor layer formation, thereby reducing total processing time while achieving the desired hydrogen concentration reduction
Solution Approach 2:
The patent utilizes parameter changes by optimizing heat treatment conditions (temperature, time, atmosphere) during film formation. By adjusting these parameters within the film formation process, the method achieves effective hydrogen removal without requiring additional dedicated heat treatment steps, thus reducing processing time while maintaining effectiveness
3Measurement precision
If multiple samples are prepared under different conditions to evaluate optimal processing, then evaluation accuracy improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies universality by using the same C-V measurement and evaluation methodology across all samples prepared under different conditions. The universal evaluation approach allows consistent comparison of carrier density measurements from multiple samples, enabling accurate determination of optimal processing conditions without requiring different measurement techniques for each sample type
Solution Approach 2:
The patent uses copying by preparing multiple samples that replicate the same structure but under different processing conditions. These copied samples allow systematic evaluation of how varying parameters (temperature, time, atmosphere) affect carrier density and hydrogen concentration, enabling identification of optimal conditions through comparison without requiring complex unique structures for each test
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
Enables the evaluation of oxide semiconductor performance, allowing for the identification of optimal processing conditions to reduce hydrogen concentration, thereby improving semiconductor device performance and enabling in-process repair by determining the need for additional heat treatment.
Implementation Method 1
obtaining a C-V characteristic by plotting a relationship between a gate voltage Vg and a capacitance C of the MOS capacitor
Implementation Method 2
performing heat treatment of the transistor when the carrier density is determined to be high
Data Source
AI summary
Many of the principles of an oxide semiconductor are still unclear and therefore there is no established method for evaluating an oxide semiconductor. Thus, an object is to provide a novel method for evaluating an oxide semiconductor. Carrier density is evaluated, and hydrogen concentration is also evaluated. Specifically, a MOS capacitor (a diode or a triode) is manufactured, and the C-V characteristics of the MOS capacitor are obtained. Then, the carrier density is estimated from the C-V characteristics obtained.