Nitride Wide Bandgap Semiconductor Material and Electronic Devices

Zhang, Jin Feng; Zhang, Jin Cheng

doi:10.1201/9781315368856

Cited by 14 publications

(24 citation statements)

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“…oxygen and carbon, in N-polar material is higher compared to the Ga-polar case. This has a negative impact on the intended electrical properties [51,58]. Despite intense investigations, devicegrade high-quality N-polar GaN epitaxial layers remain challenging.…”

Section: History and Challengesmentioning

confidence: 99%

Hot-wall MOCVD of N-polar group-III nitride materials

Zhang

2021

Linköping Studies in Science and Technology. Licentiate Thesis

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Group III-Nitride semiconductors: indium nitride (InN), gallium nitride (GaN), aluminum nitride (AlN) and their alloys continue to attract significant scientific interest due to their unique properties and diverse applications in photonic and electronic applications.Group-III nitrides have direct bandgaps which cover the entire spectral range from the infrared (InN) to the ultraviolet (GaN) and to the deep ultraviolet (AlN). This makes III-nitride materials suitable for high-efficient and energy-saving optoelectronic devices, such as light-emitting diodes (LEDs) and laser diodes (LDs). The Nobel Prize in Physics 2014 was awarded for the invention of efficient GaN blue LEDs, which further accelerated the research in the field of group III-nitride materials. GaN and related alloys are also suitable for high-temperature, high-power and high-frequency electronic devices with performance that cannot be delivered by other semiconductor technologies such as silicon (Si) and gallium arsenide (GaAs). For example, GaN-based high electron mobility transistors (HEMTs) have been widely adopted for radio frequency (RF) communication and power amplifiers, high-voltage power switches in radars, satellites, and wireless base stations for 5G.Recently, nitrogen (N)-polar group-III nitrides have drawn much attention due to their advantages over their metal-polar counterparts in e.g. HEMTs. These include feasibility to fabricate ohmic contacts with low resistance, an enhanced carrier confinement with a natural back barrier, and improved device scalability. Despite intensive research, the growth of micrometer-thick high-quality N-polar GaN based materials remains challenging.One of the major problems to develop device-quality N-polar nitrides is the high surface roughness, which results from the formation of hexagonal hillocks or step-bunching.Another significant hurdle is the unintentional polarity inversion, which reduces the crystalline quality and prohibits device fabrication.This licentiate thesis focuses on the development of N-polar AlN and GaN heterostructures on SiC substrates for HEMT RF applications. The overall aim is to exploit the advantages of the hot-wall MOCVD concept to grow high-quality N-polar HEMT structures for higher operational frequencies and improved device performance. In order to achieve this goal, special effort is dedicated to understanding the effects of growth conditions and substrate orientation on the structural properties and polarity of AlN, GaN and AlGaN grown by hot-wall MOCVD. N-polar AlN nucleation layers (NLs) with layer by layer growth mode and step-flow growth mode can be achieved on on-axis and 4 • offaxis SiC (0001), respectively, by carefully controlling V/III ratio and growth temperature. Utilizing scanning transmission electron microscopy (STEM) we have established a comprehensive picture of the atomic arrangements, local polarity and polarity evolution in AlN, Mao, my KING, thank you for your endless support and love. You are also a super father! We are all happy under your rule :) Anna...

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Section: History and Challengesmentioning

confidence: 99%

Hot-wall MOCVD of N-polar group-III nitride materials

Zhang

2021

Linköping Studies in Science and Technology. Licentiate Thesis

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“…2, it can be found that the (0002)u-rocking curve FWHM of the sample with V/III ratio of 2000 is smaller than that of the sample with V/III ratio of 500, which indicates that the sample with V/III ratio of 2000 has a lower density of screw TDs. It has been verified that screw TDs are served as a diffusion path of oxygen impurities from Al 2 O 3 substrates to GaN film [12]. Thus, reducing the density of screw TDs can prevent oxygen impurities from diffusing into N-polar GaN film, resulting in the decrease of background carrier concentration.…”

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confidence: 98%

“…It has been reported that there are many dangling bonds along the edge dislocation lines, which can introduce deep acceptor centers that may capture electrons from the conduction band in n-type semiconductors [11]. If the TDs are randomly distributed, the density of edge TDs can be determined by the following equation [12]:…”

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confidence: 99%

Study of N-polar GaN growth with a high resistivity by metal-organic chemical vapor deposition

Jiang

Zhang

Fan

et al. 2015

Vacuum

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“…One should notice that change of thickness by a few nanometers already has significant influence on the 2DEG concentration. Moreover, it is important to realize that there is certain minimum thickness of AlGaN necessary for formation of the 2DEG [66], which in the case presented here should be around 5 nm. Literature data suggest that this critical thickness could be lower, around 3 nm [109].…”

Section: Analysis and Methodsmentioning

confidence: 99%

“…Despite intensive research on those contacts to AlGaN/GaN heterostructures, obtaining high barrier and near-ideal behaviour remains challenging. There are several issues, such as for example adhesion [66], thermal stability [67] or metal diffusion during the annealing [68]. In recent years, substantial effort has been focused on the electrical properties of various Au-free Schottky metal stacks [69][70][71].…”

Section: Schottky Contactsmentioning

confidence: 99%

Gold free contacts to AlGaN/GaN heterostructures

Hajlasz¹

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Nitride Wide Bandgap Semiconductor Material and Electronic Devices

Cited by 14 publications

References 0 publications

Hot-wall MOCVD of N-polar group-III nitride materials

Hot-wall MOCVD of N-polar group-III nitride materials

Study of N-polar GaN growth with a high resistivity by metal-organic chemical vapor deposition

Gold free contacts to AlGaN/GaN heterostructures

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