4,954 research outputs found
IGBT RBSOA non-destructive testing methods: Analysis and discussion
No full textThe investigation about RBSOA limits and the study of the instabilities in high power IGBT devices, during clamped and unclamped operations can be executed by means of non-destructive experimental test circuits where the power device is switched in the presence of a protection circuit able to save it in the case of a dangerous condition to take place. This work, starting from the main non-destructive tester (NDT) proposed during the past years, supplies critical considerations and discussions about the main problems and difficulties that arise when a non-destructive experimental set-up is used for the IGBT RBSOA characterization. The authors demonstrate that the characteristics of the protection circuit must be chosen accordingly to the device that must be characterized and the possibility of saving this device may be significantly improved by a proper choice of the circuit parameters. Considerations about the influence of the parasitic stray elements in the circuit operation and the possible solutions to these problems are also investigated
Operation of SiC normally-off JFET at the edges of its safe operating area
No full textThe paper presents the results of an experimental characterization about the operation of the last generation normally-off SiC JFETs at the edges of their safe operating area. Short circuit and unclamped turn-off operations have been investigated by means of a nondestructive experimental set up where the device is switched in the presence of a protection circuit capable of limiting the energy dissipated on the device after the failure occurrence. The experimental results confirm the very good performances of the device in short circuit for which the failure can be associated only to the increase of the temperature over the limits imposed by the surface metallization. A different scenario appears for the unclamped tests where a second breakdown occurs after a quite long avalanche phase followed by the device failure. It is demonstrated that the duration of the avalanche phase depends on the temperature of the device under test. The damaged area after an avalanche failure is localized at the edge termination of the device and, in particular, at the corner between source and gate metallization
Instabilities in Silicon Power Devices: A Review of Failure Mechanisms in Modern Power Devices
No full text
Unclamped repetitive stress on 1200 V normally-off SiC JFETs
No full textAn experimental characterization of new-generation normally-off vertical channel 1200 V SiC JFETs
under unclamped repetitive stress (URS) is presented. The drain and gate leakage currents are monitored,
and their time evolution is recorded.
The degradation of the leakage characteristics has been compared with repeated short circuits tests, at
the same stress energy, thus demonstrating that different mechanisms take place in these conditions.
Furthermore, a post-failure analysis of the surface of the device by means of a optic microscope indicates
that a termination weakness could be the major cause for the device leakage increment and consequent
failure
Francesco Scorza Barcellona o della passione agiografica
No full textL'autrice traccia, sul filo dei ricordi, il profilo scientifico ed umano di Francesco Scorza Barcellona ed introduce gli studi raccolti nel volume.The author traces, on the thread of memories, the scientific and human profile of Francesco Scorza Barcelona and introduces the studies collected in the book
Behavior of power MOSFETs during heavy ions irradiation performed after γ-rays exposure
No full textThe behavior of medium voltage commercial power MOSFETs, first degraded with increasing c-rays doses
and subsequently irradiated with heavy ions, is presented. It is shown that the degradation of the gate
oxide caused by the c irradiation severely corrupt the SEE robustness and drastically modify the physical
behavior of the device under test after the impact of a heavy ion. A decrease of the critical voltages at
which destructive burnouts and gate ruptures appear has been detected in all devices previously irradiated
with c-rays, the amount of the critical voltage reduction is strictly related to the amount of the
absorbed c-rays dose. Furthermore, at the failure voltage, the behavior of the device is affected by the
conduction of a current through the gate oxide. Moreover the SEGR of the device appears at lower voltages
due to the reduction of the Fowler–Nordheim limit in the c-irradiated devices
Delle lodi di don Francesco Medici de' principi di Toscana : orazione /
No full textEngraved t.p. vignette of Medici arms. On recto of 2nd leaf is Callot's full-page engraved port. of Francesco de' Medici, son of Grand Duke Ferdinand I. It is in Lieure's 1st state. The port. also appeared the same year in Alessandro Adimari's Esequie dell' ill.mo & ecc.mo principe don Francesco Medici (Florence : Gio. Donato & Bernardino Giunti); see Lieure. Large woodcut Giunti device on p. [31].Lieure, J. Jacques Callot,Mode of access: Internet.At head of front pastedown is bookplate of Francesco Riccardi de Vernaccia (Florence, ca. 1780; see Gelli, p. 387). Below it is the label of Horatius (Orazio) Landau, with stamped shelfmark 53021. At foot is the bookplate of U. Manganelli, signed with the initials SER. A dedicatory inscription at foot of t.p. has been scratched out.Binding: modern marbled paper, backed in green vellum. Date, author & title writte on spine.Port. trimmed into the image at right margin and foot
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