Compound Semiconductors

Film Thickness and Quality

In the advancement of thin film technology through miniaturization, HORIBA proposes solutions for achieving high film deposition control, such as in-situ evaluation during the film deposition process and evaluation of thin films at the Ångström order level.

Thin film analysis in liquid: Analysis using a spectroscopic ellipsometer liquid measurement cell
In situ thin film evaluation: In-chamber wafer analysis by incorporating analytical parts into the chamber

Membrane information obtained using a spectroscopic ellipsometer

Determination of the thickness and the dispersion of the AlGaN and the GaN layer in the samples of the GaN and AlGaN films deposited on sapphire substrates.

Liquid Crystal Modulation Spectroscopic Ellipsometry is an excellent technique for the highly accurate characterization of the compound semiconductor heterostructure AlGaN / GaN. Using the MM-16 spectroscopic ellipsometer it is a straightforward procedure to determine the film thickness and optical dispersions of the complete structure even where the film is several microns thick. The detailed knowledge of the optical parameters of AlGaN alloys is crucial for example for the design of opto-electronic devices. Furthermore, from the optical parameters a calibration curve could be constructed to provide a rapid and efficient determination of the Al content in the AlGaN layers. Thus Spectroscopic Ellipsometry also proves a non-destructive technique for AlGaN alloy composition determination. This method can be equally applied to other compound emiconductors such as SiGe, II-VI semiconductors or classical III-V semiconductors.

Spectroscopic Ellipsometers are optical thin film measurement tools for determining film thickness and optical constants (n,k) of thin film structures. They are widely used in the microelectronics, display, photonics, photovoltaics, lighting, optical and functional coating, biotechnology industries. When compared with other optical metrology instruments the unique strength of spectroscopic ellipsometers are based on their highly precise and simple experimental measurements plus physical and material information derived from optical constants characterization.

Spectroscopic ellipsometry is a powerful technique for high accuracy characterization of the thickness and optical constants of GeSbTe multilayer system for rewritable optical disc applications. It was shown that measurement in the NIR range gives better accuracy for the analysis of these types of material. The use of the multiple sample analysis reduces parameter correlations and errors for the thinnest layers. Owing to the advanced modeling features included in the DeltaPsi2 software, it is a straightforward procedure to analyze such structures even with layers deposited on both sides of the substrate.

Driven by applications like LED-backlit TVs and solid-state lighting, the global LED market is growing rapidly. The main challenges for general LED lighting include reducing overall production costs and increasing efficiency and lifetimes. The performance of a LED which is characterized by its wall-plug efficiency depends on the design and overall material properties of the LED thin film structure. Ellipsomentry may be used for the accurate determination of the thickness and optical constants of the LED device for both research and industrial applications. Accurate control of thickness and refractive index is vital for the optimization of device properties and for industrial quality control.

Depth Elemental Profile Analysis

We introduce an analysis method that allows for the rapid and easy determination of the depth-directional distribution of elements in compound semiconductor thin films, where performance varies significantly depending on the composition ratio of elements.

Depth elemental profile analysis
- Elemental analysis of compound semiconductor thin films by GD-OES
Sample surface elemental analysis
- Light element distribution analysis on GaN surface by GD-OES

Cristal Defect Analysis

Reducing defects and precisely controlling impurities have become increasingly important in semiconductor devices for high-speed communication. We will introduce analysis cases illustrating this.

Compound semiconductor wafer defect evaluation
- Non-destructive wafer defect distribution evaluation using PL mapping
- Full-surface high-speed defect evaluation of 3-inch InGaP wafers
- GaN wafer defect classification evaluation
- Analysis of the same area using steady PL spectra and time-resolved measurements
Impurity analysis in compound semiconductor wafers
- Impurity analysis in GaAs wafers by cathodoluminescence

Foreign Object Detection/Analysis

Defects in wafers can also be caused by foreign matter, and we will introduce a method of microscopic elemental analysis to identify the cause of defects.

Foreign material elemental analysis of defective parts on SiC wafers
- Identification of foreign elements that cause defects on SiC wafers
Foreign matter analysis on wafers in a wide range
- Analyzing foreign objects within a few square centimeters
Reticle/mask foreign object detection
- High-throughput foreign object detection
Foreign matter removal device on wafers
- Automatic foreign matter removal device using blow & vacuum suction

Carrier Lifetime Analysis

Deposition of highly crystalline SiC epitaxial films is essential for high-performance compound semiconductors, and we will introduce a non-destructive and precise method for analyzing crystallinity after deposition.

Compound semiconductor wafer defect evaluation
- Non-destructive wafer defect distribution evaluation using PL mapping
SiC carrier lifetime analysis
- Carrier lifetime analysis of different SiC film formation conditions by PL lifetime measurement