SiC Materials And Devices, Volume 1
With contributions by recognized leaders in SiC technology and materials and device research, this book gives a comprehensive, up-to-date review of silicon carbide materials properties and devices.
TABLE OF CONTENTS SiC Materials And Devices, Volume 1
2: Turn-On Process in the Thyristors
2 Turn-On Process in the Thyristors
Turn-on processes in the thyristors depend appreciably on the width of blocking base, i.e. on the breakover voltage Vj,. The switch-on processes in 4H-SiC thyristors with V b ? 400 V were investigated in Refs. [4] [5] [6]
2.1 Turn-On Process in Low-Voltage Thyristor Structures
The device structure of low-voltage p +np~n 4H-SiC thyristor with breakover voltage Vb 400 V is shown in Fig. 1.
Fig. 1: Cross-section of low-voltagep +np -n 4H-SiC thyristor [6]
The voltage blocking p~ layer was 4.5 /nm thick and had an acceptor doping concentration of 2.8 l0 16 cm -3. The n-base had a thickness of 0.55 /im and a doping of 4.5 lO 17 cm -3. The operation area of the device was 3.6 10 -4 cm 2. The devices were turned on by 3-200 ns gate pulse. The load resistance (RL) connected in series with the thyristor was varied in the 1.1-50 ? range to obtain the desired operating current density.
Over all range of initial bias VQ and current density j up to j 10 4 A/cm 2, the time dependence of the current J in turn-on process was described well by conventional formula:
where ? r is the current rise time constant.
However, unlike Si and GaAs thyristors, the ? r in low-voltage SiC thyristors at 300 K did not depend...
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