The Effect of AlN Buffer Layer on AlGaN/GaN/AlN Double‐Heterostructure High‐Electron‐Mobility Transistor

Choi, Uiho; Jung, Donghyeop; Lee, Kyeongjae; Kwak, Taemyung; Jang, T.; Nam, Yongjun; So, Byeongchan

doi:10.1002/pssa.201900694

Cited by 12 publications

(9 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We followed the study by Freedsman et al 22 and optimized the nucleation conditions for sample B in terms of V-pit formation. The intention was to provoke different microstructural properties in all layers above the nucleation layer up to the AlGaN barrier 23,24 . As we want to focus on dislocations in the AlGaN barriers of both samples, we need to find a way to characterize them electrically.…”

Section: Resultsmentioning

confidence: 99%

“…One potential mechanism is the Al pulling effect similar to the In pulling effect in InGaN layers grown on GaN [28][29][30] . Different nucleation conditions as used in our work were shown to induce different depth profiles of the grown-in V-pit density, which in turn has an influence on stress relaxation and thus on Al incorporation 3,24,30,31 .…”

Section: Leakage Current and Relation To Dislocation Types As Mentiomentioning

confidence: 87%

See 1 more Smart Citation

The impact of dislocations on AlGaN/GaN Schottky diodes and on gate failure of high electron mobility transistors

Besendörfer

Meissner

Medjdoub

et al. 2020

Sci Rep

View full text Add to dashboard Cite

GaN epitaxially grown on Si is a material for power electronics that intrinsically shows a high density of dislocations. We show by Conductive Atomic Force Microscopy (C-AFM) and Defect Selective Etching that even for materials with similar total dislocation densities substantially different subsets of dislocations with screw component act as current leakage paths within the AlGaN barrier under forward bias. Potential reasons are discussed and it will be directly shown by an innovative experiment that current voltage forward characteristics of AlGaN/GaN Schottky diodes shift to lower absolute voltages when such dislocations are present within the device. A local lowering of the Schottky barrier height around conductive dislocations is identified and impurity segregation is assumed as responsible root cause. While dislocation related leakage current under low reverse bias could not be resolved, breakdown of AlGaN/GaN Schottky diodes under high reverse bias correlates well with observed conductive dislocations as measured by C-AFM. If such dislocations are located near the drain side of the gate edge, failure of the gate in terms of breakdown or formation of percolation paths is observed for AlGaN/GaN high electron mobility transistors.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Leakage Current and Relation To Dislocation Types As Mentiomentioning

confidence: 87%

The impact of dislocations on AlGaN/GaN Schottky diodes and on gate failure of high electron mobility transistors

Besendörfer

Meissner

Medjdoub

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…This also results in superior current collapse properties compared to AlN buffer HEMT on sapphire, which seems to be due to the improved buffer crystal quality. [ 18 ]…”

Section: Resultsmentioning

confidence: 99%

“…[13][14][15] AlN, as an ultrawide bandgap materials, is being investigated for use as a buffer in HEMT structures to address this problem. [16][17][18][19][20][21] This large band offset with the GaN channel layer offers not only the maximum vertical carrier confinement but also high thermal conductivity (340 W mK À1 ) and low thermal boundary resistance. So, it is expected to be reliable and stable when operating in harsh environments.…”

Section: Introductionmentioning

confidence: 99%

Power Performance of AlGaN/GaN High‐Electron‐Mobility Transistors with AlN Buffer on SiC Substrate at 3.5 GHz

Kim¹,

Choi²,

Kim³

et al. 2023

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

Herein, a 3.5 GHz (S‐band) power performance is reported on an AlGaN/GaN high‐electron‐mobility transistor (HEMT) with AlN buffer on SiC substrate. A 4 inch epi‐wafer is grown by high‐temperature metal–organic chemical vapor deposition. The fabricated devices with a 400 nm gate and direct current and radio‐frequency (RF) characteristics are examined. These device shows a transconductance of 233 mS mm−1 and a maximum drain current of 820 mA mm−1. The pulsed current–voltage (I–V) characteristic shows a low slump ratio with a 0.36% and 2.2% for Z1 and Z2, respectively. The power performance shows output power = 5.5 W mm−1 with 54.3% power added efficiency, and VDS was 50 V. The potential of an AlN buffer HEMT is demonstrated by the results for use in next‐generation high‐power RF devices.

show abstract

“…There have been numerous reports of epitaxial growth of AlN/GaN/AlN and AlGaN/GaN/AlN structures using different techniques and substrates. [ 12–18 ] These heterostructures have been used to demonstrate AlN‐based HEMTs for RF amplification [ 4,10,14,16,18 ] and high‐power switching applications. [ 11,19 ]…”

Section: Introductionmentioning

confidence: 99%

In Situ Crystalline AlN Passivation for Reduced RF Dispersion in Strained‐Channel AlN/GaN/AlN High‐Electron‐Mobility Transistors

Chaudhuri

Hickman

Singhal

et al. 2021

Physica Status Solidi (a)

View full text Add to dashboard Cite

The recent demonstration of ≈ 2 W mm−1 output power at 94 GHz in AlN/GaN/AlN high‐electron‐mobility transistors (HEMTs) has established AlN as a promising platform for millimeter‐wave electronics. The current state‐of‐art AlN HEMTs using ex situ‐deposited silicon nitride (SiN) passivation layers suffer from soft gain compression due to trapping of carriers by surface states. Reducing surface state dispersion in these devices is thus desired to access higher output powers. Herein, a potential solution using a novel in situ crystalline AlN passivation layer is provided. A thick, 30+ nm‐top AlN passivation layer moves the as‐grown surface away from the 2D electron gas (2DEG) channel and reduces its effect on the device. Through a series of metal‐polar AlN/GaN/AlN heterostructure growths, it is found that pseudomorphically strained ≤ 15 nm thin GaN channels are crucial to be able to grow thick AlN barriers without cracking. The fabricated recessed‐gate HEMTs on an optimized heterostructure with 50 nm AlN barrier layer and 15 nm GaN channel layer show reduction in dispersion down to 2 − 6 % compared with 20 % in current state‐of‐art ex situ SiN‐passivated HEMTs. These results demonstrate the efficacy of this unique in situ crystalline AlN passivation technique and should unlock higher mm‐wave powers in next‐generation AlN HEMTs.

show abstract

The Effect of AlN Buffer Layer on AlGaN/GaN/AlN Double‐Heterostructure High‐Electron‐Mobility Transistor

Cited by 12 publications

References 24 publications

The impact of dislocations on AlGaN/GaN Schottky diodes and on gate failure of high electron mobility transistors

The impact of dislocations on AlGaN/GaN Schottky diodes and on gate failure of high electron mobility transistors

Power Performance of AlGaN/GaN High‐Electron‐Mobility Transistors with AlN Buffer on SiC Substrate at 3.5 GHz

In Situ Crystalline AlN Passivation for Reduced RF Dispersion in Strained‐Channel AlN/GaN/AlN High‐Electron‐Mobility Transistors

Contact Info

Product

Resources

About