Impact of Electron Irradiation on the ON-State Characteristics of a 4H–SiC JBS Diode

Abstract

The ON-state characteristics of a 1.7-kV 4H-SiC junction barrier Schottky diode were studied after 4.5-MeV electron irradiation. Irradiation doses were chosen to cause a light, strong, and full doping compensation of an epitaxial layer. The diodes were characterized using Deep Level Transient Spectroscopy, C-V (T), and I-V measurements without postirradiation annealing. The calibration of model parameters of a device simulator, which reflects the unique defect structure caused by the electron irradiation, was verified up to 2000 kGy. The quantitative agreement between simulation and measurement requires: 1) the Shockley-Read-Hall model with at least two deep levels on the contrary to ion irradiation and 2) a new model for enhanced mobility degradation due to radiation defects. The diode performance at high electron fluences is shown to be limited by the doping compensation at the epitaxial layer.

Radiation resistance of wide-bandgap semiconductor power transistors

“…The irradiation can result in the embedding of the additional charge into the gate oxide and an increase of surface state density at the SiO 2 /SiC interface . Simultaneously, radiation defects introduced by electron irradiation can remove electrons from the low doped drift n ‐layer and degrade electron mobility .…”

“…These features are most likely given by a superposition of several peaks (defects) with close activation energies . Introduction rates of these defects are high (0.14 cm −1 for E1, 0.33 cm −1 for E2, and 0.11 cm −1 for E3 ). They form deep acceptor levels in the SiC bandgap which then compensate nitrogen shallow donors and cause carrier (electron) removal.…”

“…Removal of the charge in the drift region with increasing irradiation dose is also evidenced by decrease of the drain to source capacitance C DS . The second important effect of introduced radiation defects is the decrease of electron mobility in the drift region which significantly accelerates the increase of R DS_ON .…”

“…Measurement performed on 1700 V 4H‐SiC junction barrier Schottky (JBS) diodes (C3D10170H) subjected to electron irradiation showed that the epilayer used for this voltage class starts to be fully depleted of free carriers at irradiation doses higher than 700 kGy. It can be therefore expected that also 1700 V SiC MOSFETs will lose their functionality at this level of doses.…”

High Gamma Ray Tolerance for 4H-SiC Bipolar Circuits

“…Various device types of 4H-SiC, such as diodes, MOSFETs, BJTs and JFETs have been tested under different radiation environments like protons, neutrons and gamma ray [11][12][13][14][15][16][17]. Among these devices BJTs are generally considered to be the most radiation hard.…”