Effects of buffer compensation strategies on the electrical performance and RF reliability of AlGaN/GaN HEMTs

Bisi, Davide; Stocco, Antonio; Rossetto, Isabella; Meneghini, Matteo; Rampazzo, F.; Chini, Alessandro; Soci, Fabio; Pantellini, A.; Lanzieri, C.; Gamarra, Piero; Lacam, C.; Tordjman, M.; Forte-Poisson, M.A. di; Salvador, D. De; Bazzan, M.; Meneghesso, Gaudenzio; Zanoni, Enrico

doi:10.1016/j.microrel.2015.06.038

Cited by 9 publications

(4 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reasons for the formation of bulk defects in the AlGaN barrier layer and GaN buffer layer are multifaceted. Firstly, buffer traps are introduced because of the high-resistance characteristics exhibited by the GaN buffer layer, which are usually achieved through C or Fe impurity compensation [19][20][21][22][23]. The 2DEG concentration of a device may be affected by the aforementioned traps [24], which, in turn, affects parameters such as current density and threshold voltage [25].…”

Section: Types and Impacts Of Trapsmentioning

confidence: 99%

Trap Characterization Techniques for GaN-Based HEMTs: A Critical Review

Zou,

Yang,

Qiao

et al. 2023

Micromachines

View full text Add to dashboard Cite

Gallium nitride (GaN) high-electron-mobility transistors (HEMTs) have been considered promising candidates for power devices due to their superior advantages of high current density, high breakdown voltage, high power density, and high-frequency operations. However, the development of GaN HEMTs has been constrained by stability and reliability issues related to traps. In this article, the locations and energy levels of traps in GaN HEMTs are summarized. Moreover, the characterization techniques for bulk traps and interface traps, whose characteristics and scopes are included as well, are reviewed and highlighted. Finally, the challenges in trap characterization techniques for GaN-based HEMTs are discussed to provide insights into the reliability assessment of GaN-based HEMTs.

show abstract

Section: Types and Impacts Of Trapsmentioning

confidence: 99%

Trap Characterization Techniques for GaN-Based HEMTs: A Critical Review

Zou,

Yang,

Qiao

et al. 2023

Micromachines

View full text Add to dashboard Cite

show abstract

“…The stability of capacitance is very important for gallium nitride devices. The existing body of research has recognized the degradation phenomenon after stressing during the RF operation, but no clear relationship has been established between device degradation, trapping effect and capacitance, and the degradation mechanism still remains problematic [ 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

Investigation on Capacitance Collapse Induced by Secondary Capture of Acceptor Traps in AlGaN/GaN Lateral Schottky Barrier Diode

et al. 2022

View full text Add to dashboard Cite

In this study, a dedicated dynamic measurement system was used to investigate the transient capacitance and recovery process of AlGaN/GaN lateral Schottky barrier diodes (SBDs). With the consideration of acceptor traps in the C-doped buffer, the C-V characteristics and transient capacitance were measured and analyzed, and the results were simulated and explained by Silvaco TCAD (technology computer aided design). The ionization of acceptor traps and the change of electric potential were monitored in transient simulation to investigate the origin of the capacitance collapse in the SBD. The results suggest the significant impact of traps in the GaN buffer layer on the capacitance collapse of the device, and the secondary capture effect on the variation of acceptor ionization. Based on the study of transient capacitance of SBD, this work could be extended to the Miller capacitance in high electron mobility transistor (HEMT) devices. Moreover, the report on the stability of capacitance is essential for GaN devices, and could be further extended to other aspects of device research.

show abstract

“…A defined critical concentration of Fe in the channel cannot be established, since it may depend on several factors, such as the required device characteristic and applications. Generally a 800–1000 nm thick undoped GaN layer is used in standard HEMT structure in order to prevent the above mentioned effect, but this has the drawback to increase the soft‐subthreshold behavior (also known as soft‐breakdown) and to generate dispersion effects …”

Section: Introductionmentioning

confidence: 99%

Suppression of Iron Memory Effect in GaN Epitaxial Layers

Benkhelifa

Kirste

Manz

et al. 2017

Physica Status Solidi (b)

View full text Add to dashboard Cite

AlGaN/GaN High Electron Mobility Transistors (HEMTs) require a semi‐insulating buffer to compensate a high background donor concentration and to prevent parasitic effects, such as parallel conduction. Iron and carbon are typical impurities used for such purpose, since they can behave as deep acceptors in GaN layers. The former (Fe) brings as drawback a well‐known memory effect which consists in the segregation of Fe atoms through the GaN layers, requiring thick undoped layers to keep the two‐dimensional electron gas (2DEG) away from such electron traps. The latter (C), although easier to incorporate in the GaN layers and free of any memory effect, could cause current collapse. In this study we investigate the effect of differently strained epitaxial layers on Fe‐segregation. HEMT structures were grown on sapphire substrates by MOCVD. By growing the Fe‐doped layers under unusual growth conditions (low temperature, or as AlGaN), or by adding an interlayer (AlN, 5× AlN/GaN, or C‐doped GaN) between the doped and undoped epitaxial layers, we have succeeded in limiting the Fe segregation within 200 nm of undoped GaN layer instead of the typically required 800 nm, as proven by SIMS. While the morphology and the crystal quality of the HEMT structures have been affected to a very low extent, the electrical characteristics have benefitted from such interlayers. Higher carrier mobility and lower sheet resistance distinguish such epitaxial structures. Further benefits are expected by the device performance such as reduced soft‐subthreshold behavior (soft‐breakdown) and dispersion effects.

show abstract

Effects of buffer compensation strategies on the electrical performance and RF reliability of AlGaN/GaN HEMTs

Cited by 9 publications

References 27 publications

Trap Characterization Techniques for GaN-Based HEMTs: A Critical Review

Trap Characterization Techniques for GaN-Based HEMTs: A Critical Review

Investigation on Capacitance Collapse Induced by Secondary Capture of Acceptor Traps in AlGaN/GaN Lateral Schottky Barrier Diode

Suppression of Iron Memory Effect in GaN Epitaxial Layers

Contact Info

Product

Resources

About