Effect of external gettering with porous silicon on the electrical properties of Metal–Oxide–Silicon devices

We study in this paper the effect of porous silicon (PS)-based gettering procedure on electronic quality of p-type Czochralski silicon wafers. We analyzed the effect of N2 and O2 atmospheres on the gettering effectiveness. In addition, we give results on using co-gettering procedures based on the combination of PS with Aluminium (Al), and PS with phosphorus (P). Experiments are made in a closed infrared tubular furnace for temperatures ranging between 700 ∘C and 950 ∘C. The efficiency of gettering was monitored by Hall mobility of majority charge carriers deduced from Hall Effect measurement at ambient temperature of the fabricated Metal–Oxide–Silicon (MOS) devices. These results are confirmed with Capacitance-Voltage (C–V) spectroscopy technique at high frequency. Hence, in the linear region of C−2-(V ) characteristics of the Schottky diode, the slope of curves (in linear regions) decreases, which indicates an improvement of the ionized boron concentration in the p-type silicon. Results are analyzed and compared to those carried out on a reference sample (i.e.; without gettering).