Temperature dependence of current-and capacitance–voltage characteristics of an Au/4H-SiC Schottky diode

Highlights

•

I have fabricated an Au/4H-SiC Schottky diode in optimum conditions.

•

The abnormal behaviors observed at low temperatures are related to Schottky barrier inhomogeneities.

•

The barrier abnormality can be successfully commented by both multi-Gaussian distribution model and pinch-off model.

•

Thus, it is noted that multi-Gaussian distribution model is good agreement with pinch-off model to interpret abnormalities.

---

In this study, the current–voltage (I–V) and capacitance–voltage (C–V) measurements of an Au/4H-SiC Schottky diode are characterized as a function of the temperature in 50–300 K temperature range. The experimental parameters such as ideality factor and apparent barrier height presents to be strongly temperature dependent, that is, the ideality factor increases and the apparent barrier height decreases with decreasing temperature, whereas the barrier height values increase with the temperature for C–V data. Likewise, the Richardson plot deviates at low temperatures. These anomaly behaviors observed for Au/4H-SiC are attributed to Schottky barrier inhomogeneities. The barrier anomaly which relates to interface of Au/4H-SiC is also confirmed by the C–V measurements versus the frequency measured in 300 K and it is interpreted by both Tung’s lateral inhomogeneity model and multi-Gaussian distribution approach. The values of the weighting coefficients, standard deviations and mean barrier height are calculated for each distribution region of Au/4H-SiC using the multi-Gaussian distribution approach. In addition, the total effective area of the patches NA_e is obtained at separate temperatures and as a result, it is expressed that the low barrier regions influence meaningfully to the current transport at the junction. The homogeneous barrier height value is calculated from the correlation between the ideality factor and barrier height and it is noted that the values of standard deviation from ideality factor versus q/3kT curve are in close agreement with the values obtained from the barrier height versus q/2kT variation. As a result, it can be concluded that the temperature dependent electrical characteristics of Au/4H-SiC can be successfully commented on the basis of the thermionic emission theory with both models.

Keywords

• 4H-SiC; 
• Schottky diodes; 
• Schottky barrier anomalies
• 
  
• SOURCE:SCIENCEDIRECT
• 
  
• If you need more information about Temperature dependence of current-and capacitance–voltage characteristics of an Au/4H-SiC Schottky diodewww,sic4h.com please visit our website:http://www.qualitymaterial.net, send us email at powerwaymaterial@gmail.com.
• 
  

Quality improvement of single crystal 4H SiC grown with a purified β-SiC powder source

In the processing of single crystal SiC using the PVT method, defects such as micropipes and dislocations occur due to various reasons, including growth rate, temperature gradient, seed quality, pressure change and the SiC source powder. Among these factors, the SiC source powder was investigated to reduce defects in single crystal SiC. β-SiC powder was used to reduce the growth temperature and change basic properties of the particle, including microstructure, particle size and chemical composition, through the purification process. The structure of the purified β-SiC particle was changed into a spherical structure and its particle size expanded. Chemical analysis revealed reduced free carbon, oxide phases such as silica (SiO₂), silicon oxycarbide and metallic impurities. Purified β-SiC powder showed increased particle size of 37 µm and showed improved purity. With this, we grew single crystal 4H SiC and compared the micropipe and dislocation density to that of single crystal 4H SiC grown with non-purified β-SiC powder. The experimental results confirmed that the 4H SiC wafer grown by purified β-SiC powder exhibited improved quality.

Keywords

• Purified β-SiC powder; 
• Chemical composition; 
• Single crystal 4H SiC; 
• Micropipe and dislocation density
• • • 
      
    • SOURCE:SCIENCEDIRECT
    • 
      
    • If you need more information about SiC 4H, please visit our website:http://www.qualitymaterial.net, send us email at powerwaymaterial@gmail.com.
    •