Crystalline Defects

The current limitations of wafer technology are that the quality of materials is strongly affected by defects in the crystal structure. Crystalline defects are also a relatively common form of wafer defects, which are often caused by uneven heating during crystal growth. Compared with other defects, crystalline defects are not easy to be detected by manual inspection due to their relatively small size. In order to satisfy the various application needs of customers, Alfa Chemistry provides wafer crystal defect inspection services. We use professional equipment and testing technology to greatly improve testing efficiency and quality assurance.

Types of Defect

Alfa Chemistry has a first-class technical team and advanced equipment that are able to detect various types of defects. The types of defects we can detect include, but are not limited to, the following:

Alfa Chemistry's Measurement Methods

Alfa Chemistry has conducted preliminary research through optical microscopy, profiler technology and scanning electron microscopy (SEM), with the aim of proving the morphology of defects on a large scale. Then through atomic force microscopy (AFM), micro-Raman spectroscopy, polarized light microscope, photoluminescence spectroscopy, X-ray diffractometer and other methods, a more in-depth understanding of defect types can be obtained.

Fig 1. SEM micrograph of 4H-SiC low micropipe-density substrate. (Saddow S.E, et al. 1999)

Alfa Chemistry's Instrument Platforms

Alfa Chemistry's sophisticated instruments provide customers with professional and accurate test reports. Our testing Instruments include, but are not limited to, the following:

• Malvern Panalytical X-ray Diffractometer
• KLA Surface Profiler
• LVEM5 Benchtop Electron Microscope
• Atomic Force Microscope
• Micro-Raman Spectroscope
• Polarizing Microscope

Detectable Samples Include:

• Wafer specification diameter: 150mm, 200mm, 300mm.
• Material: Si, GaAs, Ge, SiC, InP.
• Conductivity: P or N type.
• Surface: Cutting, grinding, etching, polishing and patterned.
• Flat/notch: All SEMI standard flat or notch.

Please contact us if samples other than the abovementioned need to be tested.

Testing Standard

• ASTM F1726-1997 Standard Guide for Crystal Integrity Analysis of Silicon Wafers
• ASTM F1810-1997 Standard Test Method for Statistical Analysis of Silicon Wafer Erosion or Surface Defects

References

1. Saddow S.E, et al. (1999). "Silicon Carbide CVD Homoepitaxy On Wafers With Reduced Micropipe Density." Materials Science and Engineering: B.61-62: 158-160.
2. McGuire S, et al. (2018). "Automated Mapping of Micropipes in SiC Wafers Using Polarized-Light Microscope." Materials Science Forum. 924: 527-530.