Optimization of Metal‐Organic Chemical Vapor Deposition Regrown n‐GaN

Brueckner, Peter; Kirste, Lutz; Doering, Philipp; Fuchs, Theodor; Mueller, Stefan; Prescher, Mario; Quay, R.; Ambacher, O.

doi:10.1002/pssb.201900436

Cited by 12 publications

(9 citation statements)

References 18 publications

(19 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In non-alloyed ohmic contacts the main challenge remains as the choosing of appropriate mask, regrowth temperature, post-annealing treatment and achieve proper surface passivation without effecting the device performance. Today mostly studied non-alloyed ohmic contact is regrowth of n+-GaN by using Moleculer Beam Epitaxy (MBE) or Metalorganic Vapor Phase Epitaxy (MOCVD) [15]. There are various studies which solve the main challenges by introducing additional pre-post treatments which creates new instabilities or increase the cost immensely.…”

Section: Azo For Gan Based High Electron Mobility Transistor (Hemt) Application As Contactmentioning

confidence: 99%

Development of AZO TCOs with ALD for HEMT and HJSC Solar Cell Applications

et al. 2023

View full text Add to dashboard Cite

Transparent Conductive Oxide (TCO) films are widely used in optoelectronic devices, such as solar cells, LEDs, and Lasers. Utilization of these contacts directly affects the device efficiencies. Purpose of this study is to produce and optimize properties of Aluminum doped Zinc Oxide (AZO) using a vapor phase technique, Atomic Layer Deposition (ALD) for (n+) a-Si:H surface of silicon Heterojunction Solar Cells (HJSCs) and High Electron Mobility Transistor (HEMT) applications. This study is focused on the effect of the deposition temperature and aluminum atomic concentration on structural, electrical and optical properties of ALD grown AZO ohmic contact films. The results show that as-deposited films have 80-90% transmittance in the visible spectra, low resistance (2.04x10-3 ohm.cm) and mobility value of 5.25 cm2/V.s.

show abstract

Section: Azo For Gan Based High Electron Mobility Transistor (Hemt) Application As Contactmentioning

confidence: 99%

Development of AZO TCOs with ALD for HEMT and HJSC Solar Cell Applications

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Ohmic contacts for GaN HEMTs are commonly fabricated using Ti-or Ta-based metal stacks or regrown contacts. Planar metal-based contacts typically exhibit an R c of 0.2-0.4 Ω•mm, while regrown contacts achieve an R c smaller than 0.1 Ω•mm using molecular-beam epitaxy [4] or metalorganic chemical vapor deposition (MOCVD) [5,6]. However, the process of regrown contacts involves considerable complexity and planar metal-based ohmic contacts are therefore still the industrial standard.…”

Section: Introductionmentioning

confidence: 99%

Structural investigation of ultra-low resistance deeply recessed sidewall ohmic contacts for AlGaN/GaN HEMTs based on Ti/Al/Ti-metallization

Chen,

Persson,

Darakchieva

et al. 2023

Semicond. Sci. Technol.

View full text Add to dashboard Cite

This study presents a novel approach to forming low-resistance ohmic contacts for AlGaN/GaN HEMTs. The optimized contacts exhibit an outstanding contact resistance of approximately 0.15 Ω·mm. This is achieved by firstly recessing the barrier of the heterostructure to a depth beyond the channel. In this way, the channel region is exposed on the sidewall of the recess. The coverage of the Ti/Al/Ti ohmic metalization on the sidewall is ensured through tilting of the sample during evaporation. The annealing process is performed at a low temperature of 550 °C. The approach does not require precise control of the recess etching. Furthermore, the method is directly applicable to most barrier designs in terms of thickness and Al-concentration. The impact of recessed sidewall angle, thickness and ratio of Ti and Al layers, and the annealing procedure are investigated. Structural and chemical analyses of the interface between the ohmic contacts and epi-structure indicate the formation of ohmic contacts by the extraction of nitrogen from the epi-structure. The approach is demonstrated on HEMT-structures with two different barrier designs in terms of Al-concentration and barrier thickness. The study demonstrate large process window in regard to recess depth and duration of the annealing as well as high uniformity of the contact resistance across the samples, rendering the approach highly suitable for industrial production processes.

show abstract

“…[ 16 ] It is clear that experimental routes of obtaining Y‐rich AlYN alloys are to be found in order to settle this dispute. Recently, Leone et al reported on the metalorganic chemical vapor deposition (MOCVD) growth of AlYN with varied Y concentrations grown on GaN and AlN surfaces, [ 23 ] enabling new perspective on the challenges of pseudobinary nitride alloys.…”

Section: Introductionmentioning

confidence: 99%

AlYN Thin Films with High Y Content: Microstructure and Performance

Solonenko

Strube

Fammels

et al. 2023

Physica Rapid Research Ltrs

View full text Add to dashboard Cite

Pseudobinary nitride alloys display enhanced piezoelectric properties compared to their nonalloyed counterparts enabling their wide application in high‐performance transducers and acoustic wave resonators. Their fabrication remains challenging because of their inherently stochastic nature, which requires in‐depth understanding of the film growth dynamics and the interplay of deposition parameters. Herein, thin Al1−xYxN films are produced with varied yttrium content in the range from x = 0.09 to 0.28 on a gradient seed layer on 200‐mm Si substrates and investigated via various X‐ray diffraction methods, high‐resolution scanning transmission electron microscopy, nanoindentation, and atomic force microscopy. Bulk acoustic wave resonators, solidly mounted on a multilayer acoustic isolation, are fabricated to analyze the piezoelectric performance of the films and to extract corresponding material parameters via fitting of the high‐frequency electrical response by 1D Mason's model. The trend of declining coupling is explained by the lattice softening and the increase in electron density, experimentally observed by monitoring reduced elastic modulus and dielectric constant values, respectively. The absence of expected enhancement of the piezoelectric modulus is interpreted by the presence of oxygen impurities, facilitating the inhomogeneous strain of the AlYN lattice, which effectively cancels the energy flattening phenomenon, found in III–V pseudobinary alloys.

show abstract

Optimization of Metal‐Organic Chemical Vapor Deposition Regrown n‐GaN

Cited by 12 publications

References 18 publications

Development of AZO TCOs with ALD for HEMT and HJSC Solar Cell Applications

Development of AZO TCOs with ALD for HEMT and HJSC Solar Cell Applications

Structural investigation of ultra-low resistance deeply recessed sidewall ohmic contacts for AlGaN/GaN HEMTs based on Ti/Al/Ti-metallization

AlYN Thin Films with High Y Content: Microstructure and Performance

Contact Info

Product

Resources

About