Fixed interface charges between AlGaN barrier and gate stack composed of <i>in situ</i> grown SiN and Al2O3 in AlGaN/GaN high electron mobility transistors with normally off capability

Capriotti, Mattia; Alexewicz, A.; Fleury, Clément; Gavagnin, M.; Bethge, Ole; Visalli, Domenica; Derluyn, Joff; Wanzenböck, Heinz D.; Bertagnolli, E.; Pogány, D.; Strasser, G.

doi:10.1063/1.4868531

Cited by 39 publications

(18 citation statements)

References 30 publications

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“…To date, different dielectric materials, including SiO 2 , HfO 2 , Si 3 N 4 , and Al 2 O 3 , have been tested [22][23][24]. Nevertheless, due to the potential defectiveness of these wide-bandgap dielectrics [25,26] and the related interfaces with the underlying epitaxy, chargetrapping at interface-, border-, and oxide-traps still remain of great concern for the prospective implementation of GaNbased MIS (or MOS) gate technologies.…”

Section: Trapping In the Gate Insulatormentioning

confidence: 99%

Trapping mechanisms in GaN‐based MIS‐HEMTs grown on silicon substrate

Bisi

Meneghini

Hove

et al. 2015

Physica Status Solidi (a)

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In this work we report on the three dominant trapping mechanisms affecting the dynamic performance of a double-heterostructure GaN-based MIS-HEMT grown on silicon substrate. In the OFF-state, with high drain voltage and pinched-off 2DEG, the dominant mechanism is the charge-trapping in the gate-drain access region caused by the transversal drain-to-substrate potential. This effect causes the dynamic increase of the ON-resistance, and is positively temperature-dependent, thus of great concern for high-temperature operation. In the SEMI-ON-state, due to the presence of high VDS and relatively high IDS, an additional trapping mechanism emerges, involving the injection of hot electrons from the 2DEG into trap states located in the GaN-buffer or in the AlGaN barrier. This mechanism, critical in hard-switching operations, affects both the ON-resistance and the VTH. Finally, when the gate is positively biased (gate overdrive state) trapping of electrons happens in the gate dielectric layer(s), leading to strong metastable VTH instabilities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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Section: Trapping In the Gate Insulatormentioning

confidence: 99%

Trapping mechanisms in GaN‐based MIS‐HEMTs grown on silicon substrate

Bisi

Meneghini

Hove

et al. 2015

Physica Status Solidi (a)

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“…2 The key feature of the precise tuning of V th in GaN-based MISHEMTs is the control of the positive fixed charge (Q f ) at the insulator/III-N interfaces. 11 The positive Q f was reported for Al 2 O 3 /(Al, Ga)N, [12][13][14][15] SiO 2 /AlGaN, 15 and SiN/AlGaN 16,17 interfaces. Furthermore, it was well demonstrated by many groups that the amount of Q f is often comparable to the negative polarization charge (Q À pol ) at the insulator/III-N interfaces.…”

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confidence: 99%

Origin of positive fixed charge at insulator/AlGaN interfaces and its control by AlGaN composition

Matys

Stoklas

Blaho

et al. 2017

Applied Physics Letters

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The key feature for the precise tuning of Vth in GaN-based metal-insulator-semiconductor (MIS) high electron mobility transistors is the control of the positive fixed charge (Qf) at the insulator/III-N interfaces, whose amount is often comparable to the negative surface polarization charge (Qpol−). In order to clarify the origin of Qf, we carried out a comprehensive capacitance-voltage (C-V) characterization of SiO2/AlxGa1–xN/GaN and SiN/AlxGa1–xN/GaN structures with Al composition (x) varying from 0.15 to 0.4. For both types of structures, we observed a significant Vth shift in C-V curves towards the positive gate voltage with increasing x. On the contrary, the Schottky gate structures exhibited Vth shift towards the more negative biases. From the numerical simulations of C-V curves using the Poisson's equation supported by the analytical calculations of Vth, we showed that the Vth shift in the examined MIS structures is due to a significant decrease in the positive Qf with rising x. Finally, we examined this result with respect to various hypotheses developed in the literature to explain the origin of the positive Qf at insulator/III-N interfaces.

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“…113, 232102 (2018) the conduction band offset between SiN x and Al 0.25 Ga 0.75 N, and / s is the distance between the Fermi level and GaN conduction band energy in the neutral region, which is $0.3 eV. [14][15][16] Here, r AlGaN ¼ 4.2 Â 10 À6 C/cm 2 and r GaN ¼ 2.9 Â 10 À6 C/cm 2 are the absolute values of the polarization charges for the Al 0.25 Ga 0.75 N barrier and the GaN channel, 14 respectively. r SiN ;fix is the fixed charge density at the SiN x /AlGaN interface or inside the SiN x bulk, r SiN ;it is the interface charge density at the SiN x /AlGaN interface, and t AlGaN and t SiN are the thicknesses of the AlGaN barrier and SiN x dielectric, respectively.…”

Section: -3mentioning

confidence: 99%

Enhanced gate stack stability in GaN transistors with gate dielectric of bilayer SiNx by low pressure chemical vapor deposition

Huang

Jiang

Bergsten

et al. 2018

Applied Physics Letters

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We report enhanced gate stack stability in GaN metal insulator semiconductor high electron mobility transistors (MISHEMTs) by using a bilayer SiNx as the gate dielectric. To obtain the bilayer gate dielectric scheme, a thin Si-rich SiNx interlayer was deposited before a high-resistivity SiNx layer by low pressure chemical vapor deposition. The Si-rich SiNx can effectively suppress the trapping phenomenon at the interface of the dielectric/AlGaN barrier. The upper high-resistivity SiNx layer can greatly block the gate leakage current to enable a large gate swing. Compared with the MISHEMTs using a single Si-rich or high-resistivity SiNx layer, the MISHEMTs with a bilayer gate dielectric take the advantages of both, realizing a gate stack with a stable threshold voltage and low leakage current. These results thus present great potential for developing high-performance GaN MISHEMTs using the bilayer SiNx gate dielectric scheme for highly efficient power applications.

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Fixed interface charges between AlGaN barrier and gate stack composed of in situ grown SiN and Al2O3 in AlGaN/GaN high electron mobility transistors with normally off capability

Cited by 39 publications

References 30 publications

Trapping mechanisms in GaN‐based MIS‐HEMTs grown on silicon substrate

Trapping mechanisms in GaN‐based MIS‐HEMTs grown on silicon substrate

Origin of positive fixed charge at insulator/AlGaN interfaces and its control by AlGaN composition

Enhanced gate stack stability in GaN transistors with gate dielectric of bilayer SiNx by low pressure chemical vapor deposition

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