High-Performance Depletion/Enhancement-ode $\beta$ -Ga2O3 on Insulator (GOOI) Field-Effect Transistors With Record Drain Currents of 600/450 mA/mm

High pulsed current density β-Ga2O3 MOSFETs verified by an analytical model corrected for interface charge

“…Agreement between measured and theoretical values for knee voltage (V knee) and saturated drain current (IDSS) over a wide range of Sn doping concentrations is verified. A MOSFET with the highest channel charge-mobility (N d -l) product achieved a pulsed current density of 478 mA/mm at a gate voltage of þ4 V, much higher than previously reported DC values of 60 mA/mm for MOSFETs on homoepitaxial materials 13 and 90 mA/mm for ion-implanted MOSFETs, 11 and second only to nanomembrane devices which achieved 610 mA/mm at a high forward gate bias of þ120 V. 14 This indicates the performance of the material system if self-heating due to the low thermal conductivity can be mitigated by cooling techniques or less thermally stressful applications. MOSFETs were fabricated on single crystal b-Ga 2 O 3 grown by MBE on commercially available Fe-doped (010) semi-insulating substrates.…”

“…With thin or lightly doped devices, the interface charge effect on DV G and V FB is significant. In fact, thin enhancement-mode devices have been reported 14 with V off > þ75 V exceeding the band-gap- electron-affinity sum for b-Ga 2 O 3 and indicating significant thickness of the gate oxide-gallium oxide interface trap layer. In these difficult cases, Hall measurements can be used to determine l ef f , but techniques must be developed to overcome anomalies at the gate oxide-gallium oxide interface to accurately determine N d and V FB .…”

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

“…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 …”

Recent Advances in β-Ga2O3–Metal Contacts

“…Obviously, the Ohmic behavior obtained by RIE and Si + implantation together would outperform that by RIE only since Si atoms are known to be shallow donors with small activation energies in β-Ga 2 O 3 [34]. Additionally, Zhou et al reported the high-performance β-Ga 2 O 3 field-effect transistors with Ar plasma bombardment prior to contact metal deposition [52]. On the contrary, the sample without Ar bombardment exhibited Schottky contacting.…”

“…Hence, to avoid the degradation of contact characteristics at elevated annealing temperature, more complex metal stacks should be adopted. By far, Ti/Al/Au [50, 52], Ti/Au/Ni [61, 62], and Ti/Al/Ni/Au metal stacks [13, 21, 63, 64] have been employed to form electrical contacts on β-Ga 2 O 3 . But a comprehensive comparison of contact characteristics between these metal stacks is still insufficient.…”