Electrical characteristics of Ge pMOSFETs with HfO 2 , ZrO 2 , ZrO 2 /HfO 2 , and HfZrO x gate dielectrics are studied in this letter. A lower equivalent oxide thickness (EOT) is obtained in ZrO 2 device, which, however, has a higher interface trap density (D it ) due to its inferior dielectric/Ge interface. Interestingly, the Dit and sub-threshold swing of Ge pMOSFETs are clearly reduced by ZrO 2 /HfO 2 stack gate dielectric. A peak hole mobility of 335 cm 2 /V-s is achieved in ZrO 2 /HfO 2 device thanks to good dielectric/Ge interface. Furthermore, the EOT of ZrO 2 /HfO 2 device is 0.62 nm, and the leakage current is 2 × 10 -3 A/cm 2 . Therefore, a ZrO 2 /HfO 2 stack gate dielectric is promising for Ge MOSFETs.

High-k gated metal-oxide-semiconductor field-effect-transistors (MOSFETs) with Cl-2 and CF4 plasma treatments are studied in this work. A higher-k HfON with more tetragonal phase is formed by the halogen plasma treatment on interfacial layer (IL). A low inversion equivalent oxide thickness in MOSFET is obtained with the Cl-2 plasma treated IL In addition, high mobility and transconductance, and low subthreshold swing are obtained by the Cl-2 plasma treatment, which therefore is a promising interface engineering for advanced MOSFETs. (C) 2014 Elsevier Ltd. All rights reserved.

The equivalent oxide thickness in Ge MOS device is scaled down to 0.39 nm, and the leakage current is decreased as well. The improvement can be attributed to the in-situ Ge sub-oxide desorption process in an ALD chamber at 370 ° C. About 95% Ge 4+ in HfGeO x interfacial layer are obtained by H 2 O plasma process together with in-situ desorption before atomic layer deposition.