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Radiation resistance of wide‐bandgap semiconductor power transistors
Author(s) -
Hazdra Pavel,
Popelka Stanislav
Publication year - 2017
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201600447
Subject(s) - materials science , transconductance , optoelectronics , threshold voltage , transistor , radiation resistance , high electron mobility transistor , irradiation , electron , electron mobility , band gap , voltage , electrical engineering , physics , quantum mechanics , nuclear physics , engineering
Radiation resistance of state‐of‐the‐art commercial wide‐bandgap power transistors, 1700 V 4H‐SiC power MOSFETs and 200 V GaN HEMTs, to the total ionization dose was investigated. Transistors were irradiated with 4.5 MeV electrons with doses up to 2000 kGy. Electrical characteristics and introduced defects were characterized by current–voltage ( I – V ), capacitance–voltage ( C – V ), and deep level transient spectroscopy (DLTS) measurements. Results show that already low doses of 4.5 MeV electrons (>1 kGy) cause a significant decrease in threshold voltage of SiC MOSFETs due to embedding of the positive charge into the gate oxide. On the other hand, other parameters like the ON‐state resistance are nearly unchanged up to the dose of 20 kGy. At 200 kGy, the threshold voltage returns back close to its original value, however, the ON‐state resistance increases and transconductance is lowered. This effect is caused by radiation defects introduced into the low‐doped drift region which decrease electron concentration and mobility. GaN HEMTs exhibit significantly higher radiation resistance. They keep within the datasheet specification up to doses of 2000 kGy. Absence of dielectric layer beneath the gate and high concentration of carriers in the two dimensional electron gas channel are the reasons of higher radiation resistance of GaN HEMTs. Their degradation then occurs at much higher doses due to electron mobility degradation.