Reliability Evaluation of 4H-SiC JFETs Using I-V Characteristics and Low Frequency Noise

Abstract

Two sets of 4H-SiC signal-lateral JFETs were thermally aged at 400°C and 500°C in furnaces open to air for 1000 hours. I"-" V and low frequency noise measurements were performed on these devices and the results were compared against the as-fabricated sample. The data from I"-" V characterisation demonstrates that the linear and saturated drain-source current decreases monotonically with stress temperature. In addition, the linear characteristics of the JFETs have shifted approximately 1.5V along the drain-source voltage axis. Whilst the devices thermally aged at 400°C show no degradation in magnitude and behaviour in Noise Power Spectral Density (NPSD), the NPSD of 500°C stressed devices has increase approximately 30dB and it shows a full frequency spectrum of 1/ƒ dependency up to 100 kHz. A further investigation of the noise origin reveals that the Normalised Noise Power Spectral Density (NNPSD) of the aged sample is directly proportional to RDSwhich is similar to the as-fabricated sample. Thus we hypothesize that the existing noise sources have intensified possibly due to the evolution of defects.

Application of infrared thermography to non-contact testing of AD/DC power supply

“…Particularly significant are such testing and fault identification methods that enable diagnostics without interfering with a tested system or tested components. The examples of such solutions (nondestructive testing) are: quality (reliability) evaluation on the basis of inherent noise [1][2][3][4][5][6][7], Resonant Ultrasound Spectroscopy technique [8] or infrared thermography inspections [9][10][11][12][13][14][15][16].…”