Banani Sen

Effects and mechanisms of nitrogen incorporation into hafnium oxide by plasma immersion implantation

The physics and effects of nitrogen incorporation into HfO2 films were studied in detail. The authors found that only a trace amount (∼5%) of nitrogen can be introduced into the HfO2 films using plasma immersion ion-implantation technique, regardless of implantation dose. They proposed that the nitrogen incorporation is due to the filling of O vacancies (VO) and replacement of VO O neighbors in the bulk with nitrogen atoms. At the interface, the nitrogen atoms exist in the form of Hf–N and Si–N bonding, which significantly improve the interface properties of the HfO2∕Si structure. Temperature-dependent capacitance-voltage characteristics measurements indicate that both interface and oxide trap densities were greatly reduced with the incorporation of trace amount of nitrogen atoms.

Effects of aluminum incorporation on hafnium oxide film using plasma immersion ion implantation

The effects of aluminum implantation on HfO2 thin films using plasma immersion ion implantation (Al– PIII samples) are investigated. X-ray photoelectron spectroscopy measurements reveal that most of the implanted aluminum atoms accumulated near the surface region of the oxide film. The greatly reduced leakage current, smaller flatband shift and steep transition from the accumulation to the depletion region in the capacitance–voltage characteristics for Al–PIII samples indicate that both bulk oxide and interface traps are significantly reduced by aluminum incorporation. Even though the aluminum concentration at the Si/HfO2 interface is very low the results indicate that trace amount of aluminum at the interface leads to significant improvements in both material and electrical characteristics of the thin HfO2 films.

Nitrogen Incorporation into Hafnium Oxide Films by Plasma Immersion Ion Implantation

The physics and effects of nitrogen incorporation into hafnium oxide (HfO2) films were studied in detail. We found that only a trace amount (~5%) of nitrogen can be introduced into the HfO2 films by plasma immersion ion-implantation, regardless of implantation dose. We proposed that the nitrogen incorporation is mainly due to the filling of O vacancies in the as-deposited HfO2 films and the nitridation of silicide bonds at the HfO2/Si interface. Temperature-dependent capacitance–voltage and current–voltage characteristics measurements indicate that both interface and oxide trap densities were greatly reduced as the results of the nitrogen filling of the O-vacancies and the nitridation of interfacial hafnium silicide bonds.

Electrical Stability Improvement for Lanthanum Oxide Films by Nitrogen Incorporation using Plasma Immersion Ion Implantation

The effect of nitrogen implantation on thin lanthanum oxide (La2O3) films grown by e-beam evaporation are investigated using X-ray photoelectron spectroscopy (XPS), current-voltage (I-V) and capacitance-voltage (C-V) measurements. The amount of nitrogen incorporation in the oxide film by plasma immersion ion-implantation (PII) is found to be quite low (about 3% near the surface). However, the introduction of nitrogen atoms into the La2O3 network results in a significant reduction in the oxide traps and leads to a notable improvement in both material and electrical properties of the dielectric.

Electrical characteristics and reliability of hafnium oxide films with nitrogen doping

The effects of trace amount of nitrogen doping on the electrical characteristics of thin hafnium oxide have been studied. The chemical compositions and bonding structure of the dielectric film have been explored with x-ray photoelectron spectroscopy (XPS) measurements. Current-voltage (I-V) and capacitance-voltage (C-V) measurements have been conducted on nitrogen-doped hafnium oxide samples and to study the reliability of the film constant-voltage stressing has been performed. The trapping characteristics have been further revealed by conducting the I-V and C-V measurements at different temperatures ranging from 100 to 400 K. We have found that although the deep trap level due to oxygen vacancy and interface trap density due to Hf-Si bonding can be significantly suppressed with nitrogen doping; large amount of shallow traps are still present.

Characteristics of La 2 O 3 gate dielectric film with Al implantation using plasma immersion ion implantation

In this work, the effects of aluminum implantation on thin La2O3 films grown by e-beam evaporation have been investigated using x-ray photoelectron spectroscopy (XPS), current-voltage (I-V) and capacitance-voltage (C-V) measurements. The small amount of aluminum incorporated (~ 6% near the surface) in the oxide film greatly modifies both material and electrical properties of the dielectric. Reduction in the leakage current (by four orders of magnitude) and the flatband voltage shift are indications of significant removal of the bulk traps from the oxide. The steep transition from the depletion region to the accumulation region in the CV characteristics as well as the XPS results reveal the stoichiometric improvement of the interfacial layer with a reduction in the interface state density. However, the annealing conditions need to be optimized in order to have maximum reduction in oxide traps and leakage current in the Al-PIII La2O3 film.

Aluminium Incorporation in Lanthanum Oxide Films by using Plasma Immersion Ion Implantation

The physics and the effects of aluminium incorporation into lanthanum oxide (La2O3) films were studied by using x-ray photoelectron spectroscopy and electrical measurements. We found that trace amount (5% ) of aluminium incorporation in lanthanum oxide film can suppress the leakage current effectively. The bulk oxide traps and interface traps can also reduced. The percentage of aluminium incorporation into the La2O3 films by plasma immersion ion-implantation needs to be optimized to have the maximum reduction of oxide traps and to maintain the lowest leakage current.

Effects of Ambient Temperature on the Electrical Characteristics of Thin La 2 O 3 Film Grown by E-Beam Evaporation

In this work, the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of thin La 2 O 3 film deposited by e-beam evaporation were measured at several different temperatures ranging from 200 to 400 K and after constant-voltage stressing. Stressing experiment indicates significant generation of traps at duration less than 30 min. Strong temperature dependences were found both for I-V and C-V characteristics. The strong field and temperature dependence I-V curves suggested that the current conduction in the La 2 O 3 film is most likely governed by the phonon-assisted conduction. Temperature dependence high-frequency C-V curves indicate that there are a lot of shallow traps in the bulk of La 2 O 3 film and at the La 2 O 3 /Si interface. Most of the charges trapped at the interface states can be depopulated at 400 K. Those instabilities will cause serious reliability problems for MOS device operations and have to be minimized.