High-k Dielectric Trap Density Characterization Using SHG
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current characterization techniques for high-k dielectrics in semiconductor structures are either time-consuming, destructive, or difficult to implement in-line during manufacturing, failing to effectively quantify electrically active structural defects that can impact device performance and reliability.
Innovation Solution
A method and system utilizing second harmonic generation (SHG) to characterize structural defects in high-k dielectrics by transmitting incident light through the dielectric layer, causing electrons to be temporarily trapped and generating light with different energy, allowing for the measurement of trap density through analysis of the SHG spectrum's time constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical characterization techniques (CV measurements, IV) are used to characterize structural defects, then electrically active defects can be detected, but the process is time-consuming and difficult to implement in-line during manufacturing
Solution Approach 1:
The patent replaces electrical characterization techniques with optical second harmonic generation (SHG) spectroscopy. Instead of using electrical measurements (CV, IV) that are time-consuming and difficult to implement in-line, the invention uses optical methods where incident light interacts with trapped electrons in the dielectric layer to generate SHG signals. This substitution enables fast, non-destructive, in-line capable characterization while maintaining the ability to detect electrically active defects through the relationship between trapped electron density and SHG signal intensity.
Solution Approach 2:
The patent changes the measurement parameter from electrical properties to optical properties. By measuring the intensity of second harmonic generation light rather than electrical characteristics, the method achieves faster measurement speeds suitable for in-line implementation. The optical parameter (SHG signal) is directly related to the density of trapped electrons, which correlates with electrically active defects, thus maintaining measurement precision while improving productivity.
2Loss of information
If physical and optical characterization techniques (XPS, SIMS, FTIR) are used to characterize structural defects, then chemical or optical information about defects can be obtained, but these techniques are destructive, time-consuming and difficult to implement in-line
Solution Approach 1:
The patent replaces destructive physical and optical techniques (XPS, SIMS, FTIR) with non-destructive optical second harmonic generation spectroscopy. The SHG method uses light to probe the dielectric layer without causing damage, enabling repeated measurements and in-line implementation. The technique maintains information acquisition capability by detecting SHG signal intensity that correlates with trapped electron density, providing insight into defect characteristics without the drawbacks of destructive methods.
Solution Approach 2:
The patent employs a non-destructive method where the sample serves itself during measurement. The incident light and generated SHG signals allow characterization without external intervention that could damage the sample. This self-service approach enables the same dielectric layer to be characterized multiple times and integrated into the manufacturing process flow without compromising sample integrity or requiring complex sample preparation.
3Reliability
If existing characterization techniques are used, then structural defects can be detected, but they fail to provide fast, non-destructive, and in-line capable methods for quantifying electrically active defects
Solution Approach 1:
The patent substitutes time-consuming electrical and physical characterization methods with rapid optical second harmonic generation spectroscopy. The SHG measurement process is inherently fast, allowing quick assessment of trap density and device reliability. The method maintains reliability assessment capability through the direct relationship between SHG signal intensity and trapped electron density, which correlates with electrically active defects that impact device performance.
Solution Approach 2:
The patent enables preliminary characterization of the dielectric layer during or immediately after fabrication. By using fast optical SHG measurements, trap density can be assessed early in the process flow, allowing for timely process adjustments before subsequent manufacturing steps. This preliminary action reduces total characterization time while maintaining reliable defect quantification.
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 provides a fast, non-destructive, and in-line capable method to quantify trap density in high-k dielectrics, enhancing the characterization of semiconductor structures and improving device reliability by identifying electrically active defects.
Implementation Method 1
at least partially transmitting an incident light having an incident energy through the high-k dielectric layer and at least partially absorbing the incident light in the semiconductor
Implementation Method 2
The incident energy is sufficient for the electron traps filled with temporarily trapped electrons to cause generation of light having energy different from the incident energy resulting from nonlinear optical effects
Data Source
AI summary
The disclosed technology generally relates to characterization of semiconductor structures, and more particularly to optical characterization of high-k dielectric materials. A method includes providing a semiconductor structure comprising a semiconductor and a high-k dielectric layer formed over the semiconductor, wherein the dielectric layer has electron traps formed therein. The method additionally includes at least partially transmitting an incident light having an incident energy through the high-k dielectric layer and at least partially absorbing the incident light in the semiconductor. The method additionally includes measuring a nonlinear optical spectrum resulting from the light having the energy different from the incident energy, the nonlinear optical spectrum having a first region and a second region, wherein the first region changes at a different rate in intensity compared to the second region. The method further includes determining from the nonlinear optical spectrum one or both of a first time constant from the first region and a second time constant from the second region, and determining a trap density in the high-k dielectric layer based on the one or both of the first time constant and the second time constant.