Bulk and Interfacial Oxygen Defects in HfO2 Gate Dielectric Stacks: A Critical Assessment

McIntyre, Paul C.

doi:10.1149/1.2779564

Cited by 41 publications

(14 citation statements)

References 42 publications

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“…The valence band maximum (VBM) of WSe 2 lies at a higher energy level in comparison to MoS 2 and their VBM difference was determined to be 0.4 eV. HfO 2 is known to have intrinsic defects such as oxygen vacancies and interstitials 43 located within the bandgap where they can serve as electron and hole traps. According to a simulation study 44 with monoclinic HfO 2 , there is a distribution of oxygen vacancies of different charged states (positive V + , negative V − , and neutral V o ) located slightly below the mid bandgap region of HfO 2 .…”

Section: Resultsmentioning

confidence: 99%

High responsivity in MoS2 phototransistors based on charge trapping HfO2 dielectrics

et al. 2020

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Abstract2D Transition Metal Dichalcogenides hold a promising potential in future optoelectronic applications due to their high photoresponsivity and tunable band structure for broadband photodetection. In imaging applications, the detection of weak light signals is crucial for creating a better contrast between bright and dark pixels in order to achieve high resolution images. The photogating effect has been previously shown to offer high light sensitivities; however, the key features required to create this as a dominating photoresponse has yet to be discussed. Here, we report high responsivity and high photogain MoS2 phototransistors based on the dual function of HfO2 as a dielectric and charge trapping layer to enhance the photogating effect. As a result, these devices offered a very large responsivity of 1.1 × 106 A W−1, a photogain >109, and a detectivity of 5.6 × 1013 Jones under low light illumination. This work offers a CMOS compatible process and technique to develop highly photosensitive phototransistors for future low-powered imaging applications.

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Section: Resultsmentioning

confidence: 99%

High responsivity in MoS2 phototransistors based on charge trapping HfO2 dielectrics

et al. 2020

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“…The high‐κ materials such as HfO 2 is considered more suitable as gate dielectric and an insulating layer for GaN based MIS devices . In this context, the ultrathin hBN layers free from any surface defects as compared to oxide dielectrics (SiO 2 and HfO 2 ) is quite promising for MIS based devices . It has also been obtained that the dielectric strength of hBN epilayer is better than that of aluminum nitride (AlN), which is greater than 4.4 MV/cm .…”

Section: Resultsmentioning

confidence: 99%

Schottky Barrier Diode Characteristics of Graphene-GaN Heterojunction with Hexagonal Boron Nitride Interfacial Layer

Kalita

Kobayashi

Shaarin

et al. 2018

Phys. Status Solidi A

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Metal‐insulator‐semiconductor (MIS) based Schottky barrier diode (SBD) has significant importance for optoelectronics and other device applications. Here, we demonstrate the fabrication of a highly rectifying Schottky barrier diode (SBD) using a thin hexagonal boron nitride (hBN) interfacial layer in graphene and n‐type gallium nitride (n‐GaN) heterojunction. Significant reduction of reverse saturation current is obtained with the introduction of hBN layer in graphene/n‐GaN interface. The MIS based SBD shows excellent ultraviolet (UV) photoresponsivity with a light/dark ratio of ≈105 at a low reverse bias voltage (−1.5V). Temperature dependent current density‐voltage (J–V) characteristics of the graphene/hBN/n‐GaN heterojunction is investigated to elucidate the current transport behavior. The Schottky barrier height increased with increase in temperature from 0.77 to 0.98 eV in the temperature range of 298–373 K, respectively. The series resistance (RS) is also found to be temperature dependent, where RS decreased with increase in temperature. The understanding of graphene/hBN/n‐GaN heterojunction device characteristics can be significant for photodiode and switching device applications.

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“…This might be due to the formation of the Si-O interfacial layer, which causes the Hf atoms near the interface region to bond with oxygen atoms in oxygen-poor conditions. The oxygen vacancies are known to be the main cause of positive charges in HfO2 films [14,15]. The Qf decreases from 9 × 10 12 to 6.9 × 10 11 cm −2 when the annealing temperature increases from 400 to 650 °C.…”

Section: Resultsmentioning

confidence: 99%

Simulation and Fabrication of HfO2 Thin Films Passivating Si from a Numerical Computer and Remote Plasma ALD

et al. 2017

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Recombination of charge carriers at silicon surfaces is one of the biggest loss mechanisms in crystalline silicon (c-Si) solar cells. Hafnium oxide (HfO 2 ) has attracted much attention as a passivation layer for n-type c-Si because of its positive fixed charges and thermal stability. In this study, HfO 2 films are deposited on n-type c-Si using remote plasma atomic layer deposition (RP-ALD). Post-annealing is performed using a rapid thermal processing system at different temperatures in nitrogen ambient for 10 min. The effects of post-annealing temperature on the passivation properties of the HfO 2 films on c-Si are investigated. Personal computer one dimension numerical simulation for the passivated emitter and rear contact (PERC) solar cells with the HfO 2 passivation layer is also presented. By means of modeling and numerical computer simulation, the influence of different front surface recombination velocity (SRV) and rear SRV on n-type silicon solar cell performance was investigated. Simulation results show that the n-type PERC solar cell with HfO 2 single layer can have a conversion efficiency of 22.1%. The PERC using silicon nitride/HfO 2 stacked passivation layer can further increase efficiency to 23.02% with an open-circuit voltage of 689 mV.

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Bulk and Interfacial Oxygen Defects in HfO2 Gate Dielectric Stacks: A Critical Assessment

Cited by 41 publications

References 42 publications

High responsivity in MoS2 phototransistors based on charge trapping HfO2 dielectrics

High responsivity in MoS2 phototransistors based on charge trapping HfO2 dielectrics

Schottky Barrier Diode Characteristics of Graphene-GaN Heterojunction with Hexagonal Boron Nitride Interfacial Layer

Simulation and Fabrication of HfO2 Thin Films Passivating Si from a Numerical Computer and Remote Plasma ALD

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