Ge pMOSFETs with GeOx Passivation Formed by Ozone and Plasma Post Oxidation

Abstract

A comparison study on electrical performance of Ge pMOSFETs with a GeO x passivation layer formed by ozone post oxidation (OPO) and plasma post oxidation (PPO) is performed. PPO and OPO were carried out on an Al 2 O 3 /n-Ge (001) substrate followed by a 5-nm HfO 2 gate dielectric in situ deposited in an ALD chamber. The quality of the dielectric/Ge interface layer was characterized by X-ray photoelectron spectroscopy and transmission electron microscopy. The PPO treatment leads to a positive threshold voltage ( V TH ) shift and a lower I ON / I OFF ratio, implying a poor interface quality. Ge pMOSFETs with OPO exhibit a higher I ON / I OFF ratio (up to four orders of magnitude), improved subthreshold swing, and enhanced carrier mobility characteristics as compared with PPO devices. A thicker Al 2 O 3 block layer in the OPO process leads to a higher mobility in Ge transistors. By comparing two different oxidation methods, the results show that the OPO is an effective way to increase the interface layer quality which is contributing to the improved effective mobility of Ge pMOSFETs.

Highly Flexible and Asymmetric Hexagonal‐Shaped Crystalline Structured Germanium Dioxide‐Based Multistate Resistive Switching Memory Device for Data Storage and Neuromorphic Computing

“…Analysis of the Ge-3d core level line for the thin film signifies that full width at half maximum (FWHM) value of 1.41 eV with a dominant peak at ≈33.1 eV of binding energy and corresponds to GeO bonding as shown in Figure 1e. The O-1s core-level line, which has an FWHM of 1.25 eV with the dominant peak at 532.3 eV corresponds to the adsorbed oxygen and other oxygen species to the sample's surface [43][44][45] as demonstrated in Figure 1f. Apart from chemical bonding, the analysis also describes the ratio of atomic concentration of Ga, N, O, and C (Ga: 32.13%, C: 2.77%, and O: 65.10%).…”

Dark current analysis of germanium-on-insulator vertical p-i-n photodetectors with varying threading dislocation density

“…18 Thin GeO x layer has been introduced with thermal annealing, Oxygen (O 2 ) plasma, and Ozone (O 3 ) oxidization. 19,20…”

Carrier Recombination Dynamics of Surface-Passivated Epitaxial (100)Ge, (110)Ge, and (111)Ge Layers by Atomic Layer Deposited Al2O3

“…The integration of high-κ gate dielectrics such as HfO 2 and Al 2 O 3 on (100) and (110) crystal planes should not produce defects due to the effect of process temperature during deposition, rather only passivating the surface states and eliminating the interdiffusion of high-κ dielectric and channel materials. , Using these technologically important crystal planes, (100) and (110), from high electron and hole mobility Ge channel materials compared with Si along with a high-κ dielectric, one could make FinFET , or gate-all-around (GAA) NSFET − for high-density and ultralow-power CMOS. However, the interfacial defects at the high-κ (e.g., HfO 2 ) and Ge channel material would require an interface passivation layer (IPL) to control the interface state density ( D it ). , An in situ ultrathin SiO 2 passivation layer from a tris­( tert -butoxy)­silanol (Si­(OH)­(OC-(CH 3 ) 3 ) 3 ) precursor during atomic layer deposited (ALD) gate dielectric or by a Si IPL layer and/or GeO x via thermal oxidation or by ozone oxidation was prescribed as IPL layer formation strategies for subsequent Al 2 O 3 and composite Al 2 O 3 /HfO 2 dielectrics deposition. − In either case, the main objective was to reduce the D it at the high-κ/Ge heterointerface. Over the last two decades, surface recombination velocities (SRV) ≤ 1 cm/s were reported for Si, − and ultralow SRV values were made possible by superior surface passivation with low D it ≈ 10 9 –10 12 eV –1 cm –2 . − The extensive research on the surface passivation of Si with low D it over the decades has been transferred to p-Ge and n-Ge by several researchers. − Noticeably, Berghuis et al have studied the surface passivation of bulk Ge using a combination of plasma-enhanced ALD (PEALD) and thermal ALD ...…”