This paper reports on the measured dc characteristics of a SiC JFET device from room temperature up to 450°C in order to evaluate the device's capability for high-temperature operation. The authors packaged SiC JFET bare die into a dedicated high-temperature package to be able to perform experiments under extremely high ambient temperatures. The experimental results show that the device can operate at 450°C, which is impossible for conventional Si devices, but the current capability of the SiC JFET diminishes with rising temperatures. For example, the saturation current becomes 20% at 450°C with respect to the value at the room temperature.
An alternative formulation for a frequency dependent (FD) ADI-FDTD method is proposed, based on an electric flux field D tridiagonal matrix rather than an electric field matrix. The procedure for D source excitation is explained. Results show that the accuracy of the method is unaffected by the inclusion of frequency dependency in the model, compared with FD-FDTD.
The performance of Probabilistic Neural Network (PNN) in object identification has been investigated with reduced complexity retaining its remarkable recognition accuracy. A new method has been proposed to reduce the network complexity in PNN by performing the harmonics mean, geometry mean, arithmetic mean and root mean square values on the training samples. The simulation results have proven a significant improvement in network complexity reduction in PNN while maintaining the recognition accuracy. This would greatly enhance the applicability of PNNs.
GaInAsP/InP strain-compensated multiple-quantum-wire lasers (wire widths of 19nm and 27nm in a period of 100nm) with SiO2/semiconductor reflectors were realized by electron-beam lithography, CH4/H2 reactive ion etching and two-step organometallic vapor-phase-epitaxial growth processes. As a result, the threshold current densities of these quantum-wire lasers were lower than those of quantum-film lasers prepared on the same initial wafer and oscillations from the transition between the ground levels were observed at room temperature.
We carried out the evaluation of the thermal cross-talk in a 1.2µm band densely packed vertical cavity surface emitting laser (VCSEL) array for the first time. The spacing of neighboring elements is as small as 20µm. We measured the wavelength shift for different integrated elements, which gives us the temperature change, as a function of the distance from a heat source. We also carried out three-dimensional thermal modeling for the array, which shows good agreement with the experiment. It is predicted that the lasing wavelength of the array is affected by a thermal cross-talk when adjacent elements are operated at the same time.