Effect of front and back gates on β-Ga2O3 nano-belt field-effect transistors

Ahn, Shihyun; Ren, F.; Kim, Janghyuk; Oh, Sangwoo; Kim, Jihyun; Mastro, Michael A.; Pearton, S. J.

doi:10.1063/1.4960651

Cited by 103 publications

(71 citation statements)

References 41 publications

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“…[4][5][6][7] Recently, mechanically exfoliated Ga2O3 nano-membranes have been utilized to fabricate highcurrent transistors. [8][9][10][11][12][13] A record high drain current has been achieved in an exfoliated Ga2O3 field-effect transistor with diamond substrates. 14 This work demonstrates good device performance but has not quantified the heat transport across the Ga2O3-diamond interface as the Ga2O3 nano-membranes were adhered to diamond via Van der Waals forces.…”

Section: Introductionmentioning

confidence: 99%

Thermal conductance across β-Ga2O3-diamond van der Waals heterogeneous interfaces

et al. 2019

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Because of its ultra-wide bandgap, high breakdown electric field, and large-area affordable substrates grown from the melt, β-Ga2O3 has attracted great attention recently for potential applications of power electronics. However, its thermal conductivity is significantly lower than those of other wide bandgap semiconductors, such as AlN, SiC, GaN, and diamond. To ensure reliable operation with minimal self-heating at high power, proper thermal management is even more essential for Ga2O3 devices. Similarly to the past approaches aiming to alleviate selfheating in GaN high electron mobility transistors (HEMTs), a possible solution has been to integrate thin Ga2O3 membranes with diamond to fabricate Ga2O3-on-diamond lateral metalsemiconductor field-effect transistor (MESFET) or metal-oxide-semiconductor field-effect transistor (MOSFET) devices by taking advantage of the ultra-high thermal conductivity of diamond. Even though the thermal boundary conductance (TBC) between wide bandgap semiconductor devices such as GaN HEMTs and a diamond substrate is of primary importance for heat dissipation in these devices, fundamental understanding of the Ga2O3/diamond thermal interface is still missing. In this work, we study the thermal transport across the interfaces of Ga2O3 exfoliated onto a single crystal diamond. The Van der Waals bonded Ga2O3-diamond TBC is measured to be 17 -1.7/+2.0 MW/m 2 -K, which is comparable to the TBC of several physical-vapor-deposited metals on diamond. A Landauer approach is used to help understand phonon transport across perfect Ga2O3-diamond interface, which in turn sheds light on the possible TBC one could achieve with an optimized interface. A reduced thermal conductivity of the Ga2O3 nano-membrane is also observed due to additional phonon-membrane boundary scattering. The impact of the Ga2O3-substrate TBC and substrate thermal conductivity on the thermal performance of a power device are modeled and discussed. Without loss of generality, this study is not only important for Ga2O3 power electronics applications which would not be realistic without a thermal management solution, but also for the fundamental thermal science of heat transport across Van der Waals bonded interfaces.

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Section: Introductionmentioning

confidence: 99%

Thermal conductance across β-Ga2O3-diamond van der Waals heterogeneous interfaces

et al. 2019

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“…In addition, β‐Ga 2 O 3 is easy to achieve thin flakes by the cleavage along [100] direction with the lattice constant of 12.225 Å, which is larger than the other directions ([010] = 3.039 Å and [001] = 5.801 Å) . Based on this, exfoliation and transfer methods are generally used to apply the β‐Ga 2 O 3 nanomembrane with equal quality (compared with the β‐Ga 2 O 3 bulk crystal) to various types of substrates without distortion . This method also has the advantage in integrating β‐Ga 2 O 3 with other 2D semiconductor materials for the new power heterostructure application …”

Section: Introductionmentioning

confidence: 99%

A 800 V β‐Ga₂O₃ Metal–Oxide–Semiconductor Field‐Effect Transistor with High‐Power Figure of Merit of Over 86.3 MW cm⁻²

Feng

Cai

Yan

et al. 2019

Physica Status Solidi (a)

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Herein, a high‐performance β‐gallium oxide (β‐Ga2O3) metal–oxide–semiconductor field‐effect transistor (MOSFET) on sapphire substrate with a high breakdown voltage of more than 800 V and a high‐power figure of merit of more than 86.3 MV cm−2 is demonstrated. The atomic force microscopy (AFM) image and Raman peaks that are first characterized to ensure a nanomembrane with high quality are used for the device fabrication. A saturation drain current of 231.8 mA mm−1, an RON,sp of 7.41 mΩ cm2, an ON/OFF ratio of 108, and a subthreshold swing of 86 mV dec−1 are obtained at a channel doping concentration of 4.47 × 1017 cm−3 and a source‐to‐drain distance of 11.4 μm. Furthermore, a high breakdown voltage over 800 V is also achieved, corresponding to a record‐high direct current (DC) power figure of merit of 86.3 MW cm−2. Technology computer aided design (TCAD) simulation is also performed to extract the distribution of the electric field along the β‐Ga2O3 channel surface.

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“…There is significant promise in β-Ga 2 O 3 for use in electronics for extreme environments (high temperature, high radiation and high voltage switching) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] and for solar blind UV detection. 16 Ga 2 O 3 is suited to these applications because of its wide bandgap, ∼4.8 eV and high theoretical critical field strength ∼8 MV/cm (experimental values have reached 3.8 MV/cm).…”

Section: All Article Content Except Where Otherwise Noted Is Licensmentioning

confidence: 99%

Ohmic contacts on n-type β-Ga2O3 using AZO/Ti/Au

et al. 2017

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AZO interlayers between n-Ga2O3 and Ti/Au metallization significantly enhance Ohmic contact formation after annealing at ≥ 300°C. Without the presence of the AZO, similar anneals produce only rectifying current-voltage characteristics. Transmission Line Measurements of the Au/Ti/AZO/Ga2O3 stacks showed the specific contact resistance and transfer resistance decreased sharply from as-deposited values with annealing. The minimum contact resistance and specific contact resistance of 0.42 Ω-mm and 2.82 × 10-5 Ω-cm2 were achieved after a relatively low temperature 400°C annealing. The conduction band offset between AZO and Ga2O3 is 0.79 eV and provides a favorable pathway for improved electron transport across this interface.

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Effect of front and back gates on β-Ga2O3 nano-belt field-effect transistors

Cited by 103 publications

References 41 publications

Thermal conductance across β-Ga2O3-diamond van der Waals heterogeneous interfaces

Thermal conductance across β-Ga2O3-diamond van der Waals heterogeneous interfaces

A 800 V β‐Ga₂O₃ Metal–Oxide–Semiconductor Field‐Effect Transistor with High‐Power Figure of Merit of Over 86.3 MW cm⁻²

Ohmic contacts on n-type β-Ga2O3 using AZO/Ti/Au

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Effect of front and back gates on β-Ga2O3 nano-belt field-effect transistors

Cited by 103 publications

References 41 publications

Thermal conductance across β-Ga2O3-diamond van der Waals heterogeneous interfaces

Thermal conductance across β-Ga2O3-diamond van der Waals heterogeneous interfaces

A 800 V β‐Ga2O3 Metal–Oxide–Semiconductor Field‐Effect Transistor with High‐Power Figure of Merit of Over 86.3 MW cm−2

Ohmic contacts on n-type β-Ga2O3 using AZO/Ti/Au

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A 800 V β‐Ga₂O₃ Metal–Oxide–Semiconductor Field‐Effect Transistor with High‐Power Figure of Merit of Over 86.3 MW cm⁻²