Charge generated in 6H-SiC np diodes by MeV range heavy ions

Oshima, Takeshi; Iwamoto, Naoya; Onoda, Shinobu; Wagner, G.*; Ito, Hisayoshi; Kawano, Katsuyasu*

Charge induced in np Silicon Carbide (6H-SiC) diodes by heavy ions, oxygen (O), silicon (Si), nickel (Ni), and gold (Au) using a Transient Ion Beam Induced Current (TIBIC) measurement system. The slight increase in collected charge shows in a low bias region, and then, the values are saturated in a high bias region. This indicates that in the low bias region, since the length of the depletion layer is shorter than the ion range, carriers induced in deeper than the depletion layer diffuse and annihilate before they reach the depletion layer. Since the length of the depletion layer increases with increasing bias voltage, the charge collected by diodes increases with increasing bias voltage. In the case of the high bias, the length of the depletion layer is longer than the ion range. As a result, all carriers are induced in the depletion layer, and they can be collected by the electric field. Thus, This indicates that the value of collected charge does not depend on bias voltage. From the point of view of charge collection efficiency (CCE), the collected charge decrease with increasing atomic number. From the calculation, it is found that dense electron-hole pairs were generated in SiC by irradiation of ions with heavy mass. The decrease in the CCE due to ion irradiation with heavy mass can be interpreted in terms of the annihilation of e-h pairs in plasma due to the Auger recombination.