Study of Direct-Contact HfO2/Si Interfaces

Abstract

Controlling monolayer Si oxide at the HfO2/Si interface is a challenging issue in scaling the equivalent oxide thickness of HfO2/Si gate stack structures. A concept that the author proposes to control the Si oxide interface by using ultra-high vacuum electron-beam HfO2 deposition is described in this review paper, which enables the so-called direct-contact HfO2/Si structures to be prepared. The electrical characteristics of the HfO2/Si metal-oxide-semiconductor capacitors are reviewed, which suggest a sufficiently low interface state density for the operation of metal-oxide-semiconductor field-effect-transistors (MOSFETs) but reveal the formation of an unexpected strong interface dipole. Kelvin probe measurements of the HfO2/Si structures provide obvious evidence for the formation of dipoles at the HfO2/Si interfaces. The author proposes that one-monolayer Si-O bonds at the HfO2/Si interface naturally lead to a large potential difference, mainly due to the large dielectric constant of the HfO2. Dipole scattering is demonstrated to not be a major concern in the channel mobility of MOSFETs.

Farklı kapı oksitli RadFET dozimetrelerinin ışınlama öncesi elektriksel karakterizasyonlarının TCAD simülasyon programı ile değerlendirilmesi

“…Therefore, fabrication time/step is increasing with this process. However, RadFETs with high-k dielectrics have lower threshold voltages without ion implantation [27] and thus RadFETs with broader measurable dose range can be obtained. On the other hand, the investigation of the effect of the B + ion concentrations in p + regions on the electrical characteristics of RadFET is also very important for the evaluation of fabrication processes, because the variation in the concentration in these regions can affect the current and threshold voltages.…”

Electrical Properties and Interfacial Studies of HfxTi1–xO2 High Permittivity Gate Insulators Deposited on Germanium Substrates

“…Titanium doping was found to suppress the oxygen vacancies in tantalum oxide capacitors, which resulted in a significant reduction in the leakage current [38]. For the HfO 2 capacitors, there are also a considerable number of oxygen vacancies [39,40,41,42], which could potentially be suppressed when titanium is doped in the HfO 2 .…”

Peculiarities of the Interface between High-Permittivity Dielectrics and Semiconductors

“…Various processes of charging and discharging these traps can occur. Standard methods of determination of oxide and interface charges are probably incorrect in many cases; various methods give different results (Miyata, 2012). Very high values of the interface state densities (of the order of 10 13 eV −1 cm −2 ) at midgap were determined in some cases (Miyata et al, 2014).…”