Improved Electrical Characteristics of Ge MOS Devices With High Oxidation State in <inline-formula> <tex-math notation="TeX">${\rm HfGeO}_{\rm x}$ </tex-math></inline-formula> Interfacial Layer Formed by <italic>In Situ</italic> Desorption

Abstract

Ge MOS devices with about 95% Ge <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4+</sup> in HfGeO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> interfacial layer are obtained by H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O plasma process together with in situ desorption before atomic layer deposition (ALD). The equivalent oxide thickness is scaled down to 0.39 nm; the leakage current is decreased as well. The improvement can be attributed to the in situ Ge suboxide desorption process in an ALD chamber at 370 °C. The interface trap density and frequency dispersion need further process development to be reduced.