摘要
The interracial and electrical characteristics of Ge metal-oxide-semiconductor （MOS） devices with a dual passivation layer of ZrON/GeON formed by NH3- or N2-plasma treatment are investigated. The experimental results show that the NH3-plasma treated sample exhibits significantly improved interfacial and electrical properties as compared to the samples with N2-plasma treatment and no treatment： a lower interface-state density at the midgap （1.64 × 1011 cm-2, eV- 1） and gate leakage current （9.32 × 10-5 A/cm2 at Vfb ＋ 1 V）, a small capacitance equivalent thickness （1.11nm） and a high k value （32）. X-ray photoelectron spectroscopy is used to analyze the involved mechanisms. It is indicated that more GeON and less GeOx （x 〈 2） are formed on the Ge surface during NH3-plasma treatment than the NE-plasma treatment, resulting in a high-quality high-k/Ge interface, because H atoms and NH radicals in NHa-plasma can enhance volatilization of the unstable low-k GeOx, creating high-quality GeON passivation layer. Moreover, more nitrogen incorporation in ZrON/GeON induced by NHa-plasma treatment can build a stronger N barrier and thus more effectively inhibit in-diffusion of O and Ti from high-k gate dielectric and out-diffusion of Ge.
The interracial and electrical characteristics of Ge metal-oxide-semiconductor （MOS） devices with a dual passivation layer of ZrON/GeON formed by NH3- or N2-plasma treatment are investigated. The experimental results show that the NH3-plasma treated sample exhibits significantly improved interfacial and electrical properties as compared to the samples with N2-plasma treatment and no treatment： a lower interface-state density at the midgap （1.64 × 1011 cm-2, eV- 1） and gate leakage current （9.32 × 10-5 A/cm2 at Vfb ＋ 1 V）, a small capacitance equivalent thickness （1.11nm） and a high k value （32）. X-ray photoelectron spectroscopy is used to analyze the involved mechanisms. It is indicated that more GeON and less GeOx （x 〈 2） are formed on the Ge surface during NH3-plasma treatment than the NE-plasma treatment, resulting in a high-quality high-k/Ge interface, because H atoms and NH radicals in NHa-plasma can enhance volatilization of the unstable low-k GeOx, creating high-quality GeON passivation layer. Moreover, more nitrogen incorporation in ZrON/GeON induced by NHa-plasma treatment can build a stronger N barrier and thus more effectively inhibit in-diffusion of O and Ti from high-k gate dielectric and out-diffusion of Ge.
基金
Project supported by the National Natural Science Foundation of China(Nos.6127411261176100,61404055)
