Carrier transportation properties and series resistance of n-type β-FeSi₂/p-type Si heterojunctions fabricated by RF magnetron sputtering

Abstract

Heterojunctions composed of n-type β-FeSi 2 thin films and p-type Si(111) substrates were formed by radio frequency magnetron sputtering at an Ar pressure of 2.66 ' 10 %1 Pa at a substrate temperature of 560 °C. The current density-voltage (J-V ) curves of the heterojunctions measured in the dark and under illumination at room temperature showed a large leakage current under reverse bias conditions and a weak response to nearinfrared (NIR) light irradiation. From the results of the analysis of dark forward J-V curves, the dominant carrier transport mechanisms at V : 0.15 V and V > 0.15 V were considered a recombination process and a space-charge-limited current process, respectively. Both capacitance-voltage and conductance-voltage characteristics at room temperature were measured and analyzed as a function of applied frequency ( f ) ranging from 20 kHz to 2 MHz in order to estimate the series resistance (R s ) by the Nicollian-Brews method. R s was estimated as 77.79 Ω at 20 kHz. It decreased to 14.16 Ω at 2 MHz, which is expected because the charges at the interface states cannot follow the AC signal at high f values.

Production of p‐Type Si/n‐Type β‐FeSi2 Heterojunctions Using Facing‐Targets Direct‐Current Sputtering and Evaluation of Their Resistance and Interface State Density

“…The possible carrier transport mechanisms were investigated mainly by the analysis of the dark J–V curve. The dominant carrier transport mechanisms were a recombination process and a space‐charge‐limited current process at V ≤ 0.15 V and V > 0.15 V, respectively . Furthermore, the profile between R s at zero bias V and f for the heterojunctions was provided.…”

“…Furthermore, we provided the profile of the f ‐dependent R s –V characteristics and described the estimated R s values in the inversion, depletion, and accumulation regions. In the previous research, we formed the p‐type Si/n‐type β‐FeSi 2 heterojunctions by RFMS . The possible carrier transport mechanisms were investigated mainly by the analysis of the dark J–V curve.…”