Spatial, LET and Range Dependence of Enhanced Charge Collection by Single Ion Strike in 4H-SiC MESFETs

The spatial dependence of transient currents induced in 4H-SiC MESFETs by various ions with the same Linear Energy Transfer (LET) but different projected ranges is evaluated. The largest signal is observed when an ion strikes the Gate-to-Drain (G-D) recess. In addition, enhanced transient currents are detected when an ion strikes the gate and the drain. The charge enhancement mechanism is clarified by using numerical simulations. Finally we discuss the effect of LET and the projected range on the charge enhancement effect. It is found that the early stage of charge collection (less than several ns) is insensitive to the projected range and energy but depends on LET. In contrast, the later stage of charge collection are independent of LET and depend on the projected range.