Effects of AlN/GaN superlattice buffer layer on performances of AlGaN/GaN HEMT grown on silicon for sub-6 GHz applications

Hieu, Le Trung; Hsu, Heng‐Tung; Chiang, Chung-Han; Panda, Debashis; Lee, Ching-Ting; Lin, Chih-Min; Chang, Edward Yi

doi:10.1088/1361-6641/acac4b

Cited by 4 publications

(3 citation statements)

References 36 publications

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“…Furthermore, to investigate the influence of various buffer layers on the small-signal characteristics, the insertion loss of the coplanar waveguide was determined. This evaluation employed in the small signal model, including both equivalent circuit and n-cells transmission line model [35] with the dimensions of the device, has been detailed in [36]. The conductive channel layer was intentionally removed before device fabrication to avoid the effect of different 2DEG on conductor loss, as illustrated in inset figure 8.…”

Section: Resultsmentioning

confidence: 99%

Low contact resistance and high breakdown voltage of AlGaN/GaN HEMT grown on silicon using both AlN/GaN superlattice and Al_0.07Ga_0.93N back barrier layer

Hieu,

Rathaur,

et al. 2024

Semicond. Sci. Technol.

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In this study, the growth of a high-quality AlGaN/GaN high electron mobility transistor (HEMT) heterostructure on silicon (Si) by metal-organic chemical vapor deposition (MOCVD) was investigated by utilizing the both AlN/GaN superlattice (SL) and Al0.07Ga0.93N back barrier (BB) techniques. Atomic force microscope (AFM) and high-resolution x-ray diffractometer (HR-XRD) confirm low surface roughness of 0.26 – 0.34 nm and the formation of high-quality AlN/GaN SL and GaN channel. The AlGaN/GaN heterostructures exhibit high electron mobility of up to 1700 cm2/V∙s and high carrier concentration density of (1.02 – 1.06 × 1013 cm-2) for both heterostructures. The AlGaN/GaN HEMT devices demonstrate low specific contact resistivity (c) of 2.7 × 10-6 Ω·cm2 and low contact resistance (RC) of 0.3 Ω·mm for the heterostructure with BB layer. Furthermore, the DC characteristics demonstrate that incorporating Al0.07Ga0.93N BB in the heterostructure results in a 19.2% increase in lateral breakdown voltage (with a 10 µm spacing) and a 27.5% increase in vertical breakdown voltage (at 1 mA/cm2), compared to the heterostructure without Al0.07Ga0.93N BB within the AlN/GaN SL structure. Moreover, improvement of 10.6% in maximum saturation current (IDS) and 15.2% in on-resistance (RON)has been for the device fabricated on Al0.07Ga0.93N BB structure. The insertion loss of the buffer layer improves to –1.40 dB/mm at 40 GHz. Consequently, the proposed heterostructure investigated in this study demonstrates suitability for electronic device applications.

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Section: Resultsmentioning

confidence: 99%

Low contact resistance and high breakdown voltage of AlGaN/GaN HEMT grown on silicon using both AlN/GaN superlattice and Al_0.07Ga_0.93N back barrier layer

Hieu,

Rathaur,

et al. 2024

Semicond. Sci. Technol.

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“…To further investigate the effect of different Al 0.07 Ga 0.93 N interlayer thicknesses on insertion loss, coplanar waveguide (CPW) devices were fabricated and evaluated. Before processing the device fabrication, the top barrier layer of the epitaxial structure was etched away to avoid the effect from conductive channel layer, 18 the device size and buffer layer was shown in Fig. 6a.…”

Section: Resultsmentioning

confidence: 99%

High-Quality AlGaN/GaN HEMTs Growth on Silicon Using Al_0.07Ga_0.93N as Interlayer for High RF Applications

Lee,

Hieu,

Chiang

et al. 2023

ECS J. Solid State Sci. Technol.

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In this study, AlGaN/GaN high electron mobility transistor (HEMT) with different interlayer thicknesses of Al0.07Ga0.93N were grown by metal-organic chemical vapour deposition (MOCVD) is investigated. The AlGaN/GaN HEMTs have the same device’s structure, with the Al0.07Ga0.93N interlayer thickness varied from 0 to 800 nm. All of the samples demonstrate high crystal quality in the GaN channel, with low dislocation density of (1.34–3.81) × 109 cm−2 and low AFM surface roughness of 0.27–0.39 nm. The heterostructure with an interlayer exhibits better mobility (1750 cm2 V∙s−1) compared to the structure without an interlayer (1610 cm2 V∙s−1). Furthermore, the interlayer improves breakdown voltage, and reduces insertion loss. The DC characteristics show that the 300 nm-thick Al0.07Ga0.93N is beneficial in improving leakage current and iso-breakdown voltage up to 450 V at a spacing of 10 μm. The insertion loss reduces to –0.75 dB mm−1 compared to the structure without an interlayer. The device with a 300 nm-thick Al0.07Ga0.93N interlayer exhibits the potential of RF, including a measured transconductance of 440 mS∙mm−1 and cutoff frequencies of f T / f max = 48/96 GHz at a given bias point.

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“…Wide bandgap GaN and its related materials have been widely investigated in recent years for high-frequency and * Author to whom any correspondence should be addressed. high-power electronics applications [1][2][3][4], largely because of their enabling physical properties that demonstrate high-level performances in electron mobility, threshold breakdown field, saturation velocity, operating temperature, and carrier density of two-dimensional electron gas [5]. For wireless communications [6], radar sensing [7], and satellite broadcasting [8] applications, high-electron-mobility transistors (HEMTs) based on AlGaN/GaN have been under intense research mostly because of their superior highfrequency device characteristics.…”

Section: Introductionmentioning

confidence: 99%

Effect of TiN barrier layer in Cu-based ohmic contact of AlGaN/GaN high electron mobility transistor

Chang

Panda

Weng

et al. 2023

Semicond. Sci. Technol.

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Ti/TiN/Cu is established to be an enabling alternative to the better-known Au-based ohmic contact metals such as Ti/Al/Ni/Au. The Cu-based option delivers lower contact resistance and smoother surface morphology and is proven to be compatible with AlGaN/GaN HEMTs device processing. The TiN layer serves as an effective Cu-diffusion barrier as no detectable Cu-diffusion was observed when subjected to thermal treatment up to 600 ℃. There is a tendency of N-diffusion across the Ti/GaN interface near which N-deficiency in the GaN epitaxial layer and formation of a nano-sheath of TiN was found. This ultrathin layer of TiN works to further improve the ohmic performance of the electric contact, as reflected in lowered contact resistivity ρC. It is possible to manufacture the TiN thin films with low sheet resistance at a high deposition rate by adjusting the ratios between argon and nitrogen gas flows during sputtering deposition. Contact resistivity ρC, tested for the AlGaN/GaN HEMT devices fabricated on Si substrate according to the TLM standard were found to be as low as 3.65×10-6 Ω-cm2 (RC = 0.54 Ω-mm). The outcomes benchmark favourably against many reported metal-stacking structures for ohmic contacts. The robustness of surface morphology and interface sharpness against thermal treatments make the established ohmic stack structures suitable for scalable device fabrications.

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Effects of AlN/GaN superlattice buffer layer on performances of AlGaN/GaN HEMT grown on silicon for sub-6 GHz applications

Cited by 4 publications

References 36 publications

Low contact resistance and high breakdown voltage of AlGaN/GaN HEMT grown on silicon using both AlN/GaN superlattice and Al_0.07Ga_0.93N back barrier layer

Low contact resistance and high breakdown voltage of AlGaN/GaN HEMT grown on silicon using both AlN/GaN superlattice and Al_0.07Ga_0.93N back barrier layer

High-Quality AlGaN/GaN HEMTs Growth on Silicon Using Al_0.07Ga_0.93N as Interlayer for High RF Applications

Effect of TiN barrier layer in Cu-based ohmic contact of AlGaN/GaN high electron mobility transistor

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Effects of AlN/GaN superlattice buffer layer on performances of AlGaN/GaN HEMT grown on silicon for sub-6 GHz applications

Cited by 4 publications

References 36 publications

Low contact resistance and high breakdown voltage of AlGaN/GaN HEMT grown on silicon using both AlN/GaN superlattice and Al0.07Ga0.93N back barrier layer

Low contact resistance and high breakdown voltage of AlGaN/GaN HEMT grown on silicon using both AlN/GaN superlattice and Al0.07Ga0.93N back barrier layer

High-Quality AlGaN/GaN HEMTs Growth on Silicon Using Al0.07Ga0.93N as Interlayer for High RF Applications

Effect of TiN barrier layer in Cu-based ohmic contact of AlGaN/GaN high electron mobility transistor

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Low contact resistance and high breakdown voltage of AlGaN/GaN HEMT grown on silicon using both AlN/GaN superlattice and Al_0.07Ga_0.93N back barrier layer

Low contact resistance and high breakdown voltage of AlGaN/GaN HEMT grown on silicon using both AlN/GaN superlattice and Al_0.07Ga_0.93N back barrier layer

High-Quality AlGaN/GaN HEMTs Growth on Silicon Using Al_0.07Ga_0.93N as Interlayer for High RF Applications