Control of threshold voltage in E-mode and D-mode GaN-on-Si metal-insulator-semiconductor heterostructure field effect transistors by <i>in-situ</i> fluorine doping of atomic layer deposition Al2O3 gate dielectrics

Roberts, Joseph W.; Chalker, Paul R.; Lee, K. B.; Houston, P.A.; Cho, S. J.; Thayne, Iain; Guiney, Ivor; Wallis, D. J.; Humphreys, C. J.

doi:10.1063/1.4942093

Cited by 18 publications

(7 citation statements)

References 29 publications

(28 reference statements)

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“…Varieties of approaches, including gate recessed 2,3 , fluorine ion implantation 4 , p-GaN cap layer 5,6 have been exploited to achieve the normally-off behavior of GaN-based devices. The gate recessed approach is a promising technology since it enables to keep high mobility and high density of electrons without compromising the voltage threshold.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Cl2 etching on the Al2O3/GaN metal–oxide–semiconductor interface

Meyer

Boubenia

Petit-Etienne

et al. 2022

Journal of Vacuum Science &Amp; Technology B

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Controlling the plasma etching step involved in metal-oxide-semiconductor high-electron-mobility-transistor (MOSHEMT) GaN fabrication is essential for device performance and reliability. In particular, understanding the impact of GaN etching conditions on dielectric/GaN interface chemical properties is critically important. In this work, we investigate the impact of the carrier wafers (Si, photoresist, SiO2, and Si3N4) used during the etching of GaN in chlorine plasma on the electrical behavior of Al2O3/n-GaN metal–oxide–semiconductor (MOS) capacitors. X-ray Photoelectron spectroscopy (XPS) analyses show that the Al2O3/GaN interface layer contains contaminants from the etching process after the Al2O3 deposition. Their chemical nature depends on the plasma chemistry used as well as the chemical nature of the carrier wafer. Typically, Cl and C are trapped at the interface for all substrates. In the particular case of Si carrier wafer, a significant amount of SiOx is present at the Al2O3/GaN interface. The capacitance–voltage (C–V) characteristics of the MOS capacitors indicate that the presence of Si residues at the interface shifts the flat band voltage to negative values, while the presence of Cl or C at the interface increases the hysteresis. We demonstrate that introducing an in situ plasma cleaning treatment based on N2/H2 gas, before the atomic layer deposition, allows the removal of most of the residues except silicon and suppresses the hysteresis.

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Section: Introductionmentioning

confidence: 99%

Influence of the Cl2 etching on the Al2O3/GaN metal–oxide–semiconductor interface

Meyer

Boubenia

Petit-Etienne

et al. 2022

Journal of Vacuum Science &Amp; Technology B

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“…A 100 nm SiN x passivation layer was deposited by Plasma-Enhanced Chemical Vapor Deposition (PECVD), into which a 1.5 µm gate window was opened for F-implantation using a reactive ion etching process. In order to obtain E-mode operation, F-implantation was carried out in an inductively coupled plasma chamber with a 40 sccm (standard cubic centimeter per minute) CHF 3 34 ] for details). The structure was then annealed at 500 °C for 5 minutes under a nitrogen gas environment in a rapid thermal annealing chamber.…”

Section: Methodsmentioning

confidence: 99%

Nanoscale structural and chemical analysis of F-implanted enhancement-mode InAlN/GaN heterostructure field effect transistors

Tang

Lee

Guiney

et al. 2018

Journal of Applied Physics

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We investigate the impact of a fluorine plasma treatment used to obtain enhancement-mode operation on the structure and chemistry at the nanometer and atomic scales of an InAlN/GaN field effect transistor. The fluorine plasma treatment is successful in that enhancement mode operation is achieved with a +2.8 V threshold voltage. However, the InAlN barrier layers are observed to have been damaged by the fluorine treatment with their thickness being reduced by up to 50%. The treatment also led to oxygen incorporation within the InAlN barrier layers. Furthermore, even in the as-grown structure, Ga was unintentionally incorporated during the growth of the InAlN barrier. The impact of both the reduced barrier thickness and the incorporated Ga within the barrier on the transistor properties has been evaluated theoretically and compared to the experimentally determined two-dimensional electron gas density and threshold voltage of the transistor. For devices without fluorine treatment, the two-dimensional electron gas density is better predicted if the quaternary nature of the barrier is taken into account. For the fluorine treated device, not only the changes to the barrier layer thickness and composition, but also the fluorine doping needs to be considered to predict device performance. These studies reveal the factors influencing the performance of these specific transistor structures and highlight the strengths of the applied nanoscale characterisation techniques in revealing information relevant to device performance.

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“…It is usually reported that the nitrogen vacant sites (V N ) act as the major source of free electrons and carrier traps ,− that may degrade the device properties over prolonged bias stress. To passivate such defects, researchers attempted fluorine plasma treatment or fluorine doping in nitride semiconductors. − …”

Section: Introductionmentioning

confidence: 99%

Effects of Fluorine Doping on the Electrical Performance of ZnON Thin-Film Transistors

Kim

Park

Kim

et al. 2017

ACS Appl. Mater. Interfaces

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In this work, the effects of fluorine incorporation in high mobility zinc oxynitride (ZnON) semiconductor are studied by both theoretical calculations and experimental evaluation of thin film transistors (TFTs). From density functional theory (DFT) calculations, fluorine acts as a carrier suppressor in the ZnON matrix when it substitutes a nitrogen vacant site (V). Thin films of ZnON and ZnON:F were grown by reactively cosputtering Zn metal and ZnF targets, and their electrical, physical, and chemical characteristics were studied. X-ray photoelectron spectroscopy (XPS) analyses of the nitrogen 1s peaks in ZnON and ZnON:F suggest that as the fluorine incorporation increases, the relative fraction of Zn-N bonds from stoichiometric ZnN increases. On the other hand, the Zn-N bond characteristics arising from nonstoichiometric ZnN and N-N bonds decrease, implying that indeed fluorine anions have an effect of passivating the N-related defects. The corresponding TFTs exhibit optimum transfer characteristics and switching ability when approximately 3.5 atomic percent of fluorine is present in the 40 nm thick ZnON:F active layer.

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Control of threshold voltage in E-mode and D-mode GaN-on-Si metal-insulator-semiconductor heterostructure field effect transistors by in-situ fluorine doping of atomic layer deposition Al2O3 gate dielectrics

Cited by 18 publications

References 29 publications

Influence of the Cl2 etching on the Al2O3/GaN metal–oxide–semiconductor interface

Influence of the Cl2 etching on the Al2O3/GaN metal–oxide–semiconductor interface

Nanoscale structural and chemical analysis of F-implanted enhancement-mode InAlN/GaN heterostructure field effect transistors

Effects of Fluorine Doping on the Electrical Performance of ZnON Thin-Film Transistors

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