Electrical properties of an epitaxial Si film prepared by RF magnetron plasma at low temperature

This article reports the formation of epitaxial Si film that were formed by directly depositing a Sb-doped n-type epilayer on a p-type substrate by using a DC bais RF magnetron sputter system at a low temperature of 400 °C and a conventional vacuum of 5×10−7 Torr. In addition, the plasma parameters were quantitatively investigated to examine the deposition condition. The electron density (ne) of about 1017 m−3 was obtained at the plasma region under the conditions where gas pressure was 3 mTorr, the power of the RF source was 350 W and the electron temperature (Te) and ion saturation current (I0) were in the range of 3-4 eV and 1-1.5 mA/cm2, respectively. The p-n junction diode fabricated by the Si epitaxy shows, under optimum conditions, a reverse current density (RCD) as low as 9.5×10−6 mA/cm2 at a reverse bias voltage of 5 V and an ideality factor of 1.05. The reverse current density has a good correlation with the crystallinity of the deposited films, which, in turn, depends on deposition gas pressures and substrate biases.