Atomic-layer-deposited Al2O3 and HfO2 on GaN: A comparative study on interfaces and electrical characteristics

Chang, Yang-Chyuan; Huang, M. L.; Chang, Yang-Hua; Lee, Y.J.; Chiu, H. C.; Kwo, J.; Hong, M.

doi:10.1016/j.mee.2011.03.098

Cited by 73 publications

(49 citation statements)

References 21 publications

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“…The XPS spectra within the C 1s region from both HCl/HF-and NH 4 OH-cleaned samples are presented in Fig. 4.…”

Section: Resultsmentioning

confidence: 99%

“…In particular, both treated samples result in a lower contribution from the middle subcomponent (nominally C-O or C-N) than the GaN-only surface. For the GaN-only surface, this subcomponent makes up 14% of the total C1s signal, but only 6% in the HCl/HF treated interface and 2% in the NH 4 OH treated interface, suggesting that both treatments reduce C-O single bonds on the GaN surface. However, as evident in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The second piece underwent a basic (alkaline) treatment consisting of five minutes in NH 4 OH (30% in water), followed by a five minute DI rinse, and blow-drying with dry N 2 . In the remainder of the text we refer to these two processes as the "HCl/HF clean" and the "NH 4 OH clean", respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Al 2 O 3 has, in particular, received much attention as a possible gate dielectric because of its potential to provide low leakage and low interface state densities. [4][5][6][7] Nonetheless, prior work indicates that the initial conditions of the GaN surface can significantly influence the quality of the resultant interface.…”

mentioning

confidence: 99%

“…15,16 Of particular concern in these studies, was removal of oxides and organics from the surface. A 1999 study by Koyama et al compared a combined HCl and HF treatment to a NH 4 OH treatment using XPS, showing that both treatments resulted in oxide removal. 12 However, reports have conflicted regarding which of these two results in lower carbon concentration.…”

mentioning

confidence: 99%

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Impact of Surface Treatment on Interface States of ALD Al₂O₃/GaN Interfaces

Jackson

Arehart

Grassman

et al. 2017

ECS J. Solid State Sci. Technol.

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Two surface treatments of GaN, prior to atomic layer deposition (ALD) of Al 2 O 3 , were compared to investigate electronic and chemical interface properties: (1) HCl followed by HF and (2) NH 4 OH. Constant capacitance deep level transient and optical spectroscopies (CC-DLTS/CC-DLOS) and X-ray photoelectron spectroscopy (XPS) were used to study the impact of the surface treatments on the interface state density (D it ) and the chemical composition of the Al 2 O 3 /GaN interface, respectively. It was determined that the HCl/HF treatment resulted in 3-10 times higher D it near the GaN conduction band, while the NH 4 OH treatment resulted in nearly 10 times higher D it deeper in the GaN bandgap. XPS revealed that the HCl/HF treatment left residual adsorbed fluorine atoms at the interface and that the NH 4 OH treatment resulted in a higher concentration of carbon near the Al 2 O 3 /GaN interface. These results are discussed in relation to the relevant literature in attempt to understand the relationship between the chemical composition at the interface and the observed differences in D GaN metal-insulator-semiconductor high electron mobility transistors (MISHEMTs) are typically used for power electronics applications, and being considered for highly-scaled and enhancementmode operation in radio-frequency (RF) applications. In these applications, a metal-insulator-semiconductor (MIS) device structure can result in decreased gate leakage current and higher breakdown voltages versus the traditional Schottky-based HEMT structure. However, the insulator-semiconductor interface can lead to high concentrations of interface states that can negatively affect device performance and reliability.1-3 Thus, various groups have focused on improving possible gate dielectrics to reduce surface states and decrease gate leakage while maintaining small equivalent oxide thicknesses. Al 2 O 3 has, in particular, received much attention as a possible gate dielectric because of its potential to provide low leakage and low interface state densities. [4][5][6][7] Nonetheless, prior work indicates that the initial conditions of the GaN surface can significantly influence the quality of the resultant interface.8 Processes to clean the GaN surface have been a topic of research for the last two decades, although early studies primarily focused on preparing the surface for metallization; 9-13 this extensive work was well summarized by Long et al.14 More recently, the topic of surface treatment before dielectric deposition has become a topic of interest, as the search for optimal dielectric materials for use with the GaN material system has grown. 15,16 Of particular concern in these studies, was removal of oxides and organics from the surface. A 1999 study by Koyama et al. compared a combined HCl and HF treatment to a NH 4 OH treatment using XPS, showing that both treatments resulted in oxide removal.12 However, reports have conflicted regarding which of these two results in lower carbon concentration. 13,16 In the broader GaN-related literatu...

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“…The XPS spectra within the C 1s region from both HCl/HF-and NH 4 OH-cleaned samples are presented in Fig. 4.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Impact of Surface Treatment on Interface States of ALD Al₂O₃/GaN Interfaces

Jackson

Arehart

Grassman

et al. 2017

ECS J. Solid State Sci. Technol.

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Challenges for energy efficient wide band gap semiconductor power devices

Roccaforte

Fiorenza

Greco

et al. 2014

Phys. Status Solidi A

113

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Wide band gap semiconductors, and in particular silicon carbide (4H‐SiC) and gallium nitride (GaN), are very promising materials for the next generation of power electronics, to guarantee an improved energy efficiency of devices and modules. As a matter of fact, in the last decade intensive academic and industrial research efforts have resulted in the demonstration of both 4H‐SiC MOSFETs and GaN HEMTs exhibiting VnormalB2/Ron performances well beyond the silicon limits. In this paper, some of the present scientific challenges for SiC and GaN power devices technology are reviewed. In particular, the topics selected in this work will be the SiO2/SiC interface passivation processes to improve the channel mobility in 4H‐SiC MOSFETs, the current trends for gate dielectrics in GaN technology and the viable routes to obtain normally‐off HEMTs.

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Effects of trimethylaluminium and tetrakis(ethylmethylamino) hafnium in the early stages of the atomic-layer-deposition of aluminum oxide and hafnium oxide on hydroxylated GaN nanoclusters

2013

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We calculate the interactions of two atomic layer deposition (ALD) reactants, trimethylaluminium (TMA) and tetrakis(ethylmethylamino) hafnium (TEMAH) with the hydroxylated Ga-face of GaN clusters when aluminum oxide and hafnium oxide, respectively, are being deposited. The GaN clusters are suitable as testbeds for the actual Ga-face on practical GaN nanocrystals of importance not only in electronics but for several other applications in nanotechnology. We find that TMA spontaneously interacts with hydroxylated GaN; however it does not follow the atomic layer deposition reaction path unless there is an excess in potential energy introduced in the clusters at the beginning of the optimization, for instance, using larger bond lengths of various bonds in the initial structures. TEMAH also does not interact with hydroxylated GaN, unless there is an excess in potential energy. The formation of a Ga-N(CH3)(CH2CH3) bond during the ALD of HfO2 using TEMAH as the reactant without breaking the Hf-N bond could be the key part of the mechanism behind the formation of an interface layer at the HfO2/GaN interface.

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Atomic-layer-deposited Al2O3 and HfO2 on GaN: A comparative study on interfaces and electrical characteristics

Cited by 73 publications

References 21 publications

Impact of Surface Treatment on Interface States of ALD Al₂O₃/GaN Interfaces

Impact of Surface Treatment on Interface States of ALD Al₂O₃/GaN Interfaces

Challenges for energy efficient wide band gap semiconductor power devices

Effects of trimethylaluminium and tetrakis(ethylmethylamino) hafnium in the early stages of the atomic-layer-deposition of aluminum oxide and hafnium oxide on hydroxylated GaN nanoclusters

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Atomic-layer-deposited Al2O3 and HfO2 on GaN: A comparative study on interfaces and electrical characteristics

Cited by 73 publications

References 21 publications

Impact of Surface Treatment on Interface States of ALD Al2O3/GaN Interfaces

Impact of Surface Treatment on Interface States of ALD Al2O3/GaN Interfaces

Challenges for energy efficient wide band gap semiconductor power devices

Effects of trimethylaluminium and tetrakis(ethylmethylamino) hafnium in the early stages of the atomic-layer-deposition of aluminum oxide and hafnium oxide on hydroxylated GaN nanoclusters

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Impact of Surface Treatment on Interface States of ALD Al₂O₃/GaN Interfaces

Impact of Surface Treatment on Interface States of ALD Al₂O₃/GaN Interfaces