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

Abstract

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.