Laser Deflection Measurements for the Determination of Temperature and Charge Carrier Distributions in 4H-SiC Power Diodes

Dorothea Werber; Gerhard Wachutka

doi:10.4028/www.scientific.net/MSF.615-617.267

Paper Titles

Characterization of Screw Dislocations in a 4H-Silicon Carbide Diode Using X-Ray Microbeam Three-Dimensional Topography
p.251

Influence of Structural Defects on Carrier Lifetime in 4H Epitaxial Layers, Studied by High Resolution Optical Lifetime Mapping
p.255

Photoluminescence-Topography of the p-Type Doped SiC Wafers for Determination of Doping Inhomogeneity
p.259

Temperature Dependence and Selective Excitation of the Phosphorus Related Photoluminescence in 4H-SiC
p.263

Laser Deflection Measurements for the Determination of Temperature and Charge Carrier Distributions in 4H-SiC Power Diodes
p.267

Dislocation-Induced Birefringence in Silicon Carbide
p.271

Two Dimensional X-Ray Diffraction Mapping of Basal Plane Orientation on SiC Substrates
p.275

An Effective Method of Characterization of SiC Substrates
p.279

Carrier Generation Lifetime in 4H-SiC Epitaxial Wafers
p.283

HomeMaterials Science ForumMaterials Science Forum Vols. 615-617Laser Deflection Measurements for the...

Laser Deflection Measurements for the Determination of Temperature and Charge Carrier Distributions in 4H-SiC Power Diodes

Abstract:

A change of the electron and hole densities n and p and of the lattice temperature T modulates the real optical refractive index nopt of the device under test. In the forward conducting state the electron and hole distributions n(x) and p(x) in the i-region of the device are generated by the action of carrier injection from the n- and p-emitters. The device is locally heated by Joule and recombination heat, leading to a temperature distribution T(x). The gradients of temperature and charge carrier densities cause a spatial modulation of the real refractive index nopt(x). A laser beam transmitted orthogonally to the direction of current flow of the device is deflected by the gradient of nopt(x). Concurrent deflections caused simultaneously by the carrier gradients on the one side and by the temperature gradient on the other side can be discriminated by their different time constants.