Articles you may be interested inHigh quality HfO2/p-GaSb(001) metal-oxide-semiconductor capacitors with 0.8nm equivalent oxide thickness Appl. Phys. Lett. 105, 222103 (2014); 10.1063/1.4903068 Modeling and analysis of the admittance characteristics of n+ metal-oxide-semiconductor capacitors with oxide and interface states -Gd0.25Ga0.15O0.6/Ga2O3 on In0.53Ga0.47AsLow interfacial trap density and sub-nm equivalent oxide thickness in In0.53Ga0.47As (001) metal-oxidesemiconductor devices using molecular beam deposited HfO2/Al2O3 as gate dielectrics Appl. Phys. Lett. 99, 042908 (2011); 10.1063/1.3617436Engineering of threshold voltages in molecular beam epitaxy-grown Al 2 O 3 ∕ Ga 2 O 3 ( Gd 2 O 3 ) ∕ In 0.2 Ga 0.8 As J.An equivalent oxide thickness about 1 nm for Ga 2 O 3 ͑Gd 2 O 3 ͒ ͑GGO͒ on In 0.2 Ga 0.8 As has been achieved by employing a thin in situ deposited 3 nm thick Al 2 O 3 protection layer. The dual gate oxide stacks of the Al 2 O 3 / GGO ͑33, 20, 10, 8.5, and 4.5 nm͒/In 0.2 Ga 0.8 As/ GaAs metal-oxide-semiconductor ͑MOS͒ capacitors remain amorphous after rapid thermal annealing up to 800-850°C, accompanied with atomically sharp smooth oxide/semiconductor interfaces. Well behaved capacitance-voltage ͑C-V͒ curves of the MOS diodes have shown sharp transition from depletion to accumulation with small flatband voltage ͑1.1 V for Au metal gate and 0.1 V for Al͒, and weak frequency dispersion ͑1.5%-5.4%͒ between 10 and 500 kHz at accumulation capacitance. Low leakage current densities ͓3.1ϫ 10 −5 and 2.5ϫ 10 −9 A / cm 2 at V = V fb + 1 V for Al 2 O 3 ͑3 nm͒ / GGO͑4.5 and 8.5 nm͔͒, a high dielectric constant around 14-16 of GGO for all tested thicknesses, and a low interfacial density of states ͑D it ͒ in the low 10 11 cm −2 eV −1 have also been accomplished.

Articles you may be interested inEffect of indium concentration on InGaAs channel metal-oxide-semiconductor field-effect transistors with atomic layer deposited gate dielectric J. Vac. Sci. Technol. B 29, 040601 (2011); 10.1116/1.3597199 Self-aligned inversion-channel In 0.2 Ga 0.8 As metal-oxide-semiconductor field-effect transistor with molecular beam epitaxy Al 2 O 3 / Ga 2 O 3 ( Gd 2 O 3 ) as the gate dielectric J. Vac. Sci. Technol. B 29, 03C122 (2011); 10.1116/1.3565057 Electrical properties of HfTiON gate-dielectric metal-oxide-semiconductor capacitors with different Si-surface nitridations Appl. Phys. Lett. 91, 052902 (2007); 10.1063/1.2767177 Enhancement-mode InP n -channel metal-oxide-semiconductor field-effect transistors with atomic-layerdeposited Al 2 O 3 dielectrics Appl. Phys. Lett. 91, 022108 (2007); 10.1063/1.2756106Depletion-mode InGaAs metal-oxide-semiconductor field-effect transistor with oxide gate dielectric grown by atomic-layer deposition

The scalability of molecular beam epitaxy grown Ga2O3(Gd2O3)∕In0.2Ga0.8As∕GaAs with in situ Al2O3 capping layers has been studied, in which the InGaAs surface Fermi level has been unpinned. The electrical and structural properties were improved with rapid thermal annealing to high temperatures of 800°C under N2 flow. As Ga2O3(Gd2O3) is scaled down to 8.5nm, the dielectric constant maintained at 14–15, similar to those of thicker oxides, resulting in an equivalent oxide thickness of 2.3nm. A low gate oxide leakage current density of 10−9A∕cm2 at ∣VG−Vfb∣=1, small flatband voltage shift (ΔVfb), low interfacial density of states (Dit) of (1–3)×1011cm−2eV−1 have been achieved.

Electrical characteristics of oxide-In 0.2 Ga 0.8 As interface in ultra-high vacuum (UHV)-deposited Al 2 O 3 (3nm)/Ga 2 O 3 (Gd 2 O 3 ) (8.5nm) on n-and p-In 0.2 Ga 0.8 As/GaAs are studied. Capacitance-voltage (C-V) measurements under light illumination and under wide range of temperatures as well as corresponding conductance-voltage (G-V) measurements were carried out. Extremely high-quality interfaces with free-moving Fermi-level near the conductance and valence band-edges (regions close to E c and E v ) are revealed for the Ga 2 O 3 (Gd 2 O 3 )/In 0.2 Ga 0.8 As system.

GaN, with a high saturation velocity at high electrical field, low off-state drain currents, a high critical electrical field (up to 3 MV/cm), and high-quality epi-layers grown on Si, is now being considered as a channel candidate for technology beyond Si CMOS. Moreover, the aggressive scaling of CMOS device has demanded alternative high K gate dielectrics replacing conventional SiO2. Previous studies of several high K gate dielectrics for GaN MOS devices, such as Ga2O3(Gd2O3) [1], HfO2 [2], MgO [3], and Si3N4 [4], have resulted in excellent diode properties. However, characteristics of the inversion-channel device, e.g. the drain current-voltage behavior, were far inferior to those of the Si counterpart.In this work, inversion n-channel GaN MOSFETs using atomic-layer-deposited (ALD) A1203 as a high K gate dielectric have demonstrated for the first time electrical performance close to those of the Si based MOSFETs. Fig. 1 shows a cross-sectional schematic of the device structure, with its planar view (by SEM) shown in Fig. 2. Well-behaved drain I-V characteristic of a GaN MOSFET with 4x 100 pm gate dimension are shown in Fig. 3; the maximum drain current is 3.5 mA/mm with the device biased to 10 V in gate voltage and 15 V in drain voltage. At drain voltage of 0.1 V, high loi/Ioff ratio, 3 x105, is achieved at a very low off-state leakage of 4x1 013A/tm shown in Fig. 4. The threshold voltage of 2.8 V, mainly due to difference in work function between p-GaN and gate metal of Pt, was extracted along with the sub-threshold slope of 290 mV/dec. The scaling characteristic of drain current versus different gate lengths is shown in Fig. 5. Our device performance are markedly improved compared to the previous results of GaN MOSFETs with high K dielectrics [1,3,4].Both MOSFET and MOS capacitor (MOSCAP) have shown very low leakage current densities of 10-8-1 0-9 A/cm2 even at an E field of 4MV/cm (Fig. 6). C-V curves with frequencies varying from 1 k Hz to 100 kHz show clear accumulation, depletion, and deep depletion (Fig. 7), as well as a dielectric constant of 7.5. The deep depletion occurred due to the low intrinsic carrier concentration (ni~A010cm-3). The interfacial density of states (Dit) was calculated to be 5 x 101 cm-2 eV-1 near the midgap by the Terman method, shown in the inset of Fig. 7. The J-Eg curves are re-plotted in the form of ln(J/Eox2) versus 1/Eox, where linearity is realized by the Fowler-Nordheim tunneling mechanism (Fig. 8). The conduction-band offset (AEc) of 1.9 eV was determined. A1203 with a band gap of -7eV[5] is an excellent dielectric for GaN (band gap of 3.2 eV) compared to other high K materials with lower band gaps. The A1203/GaN interface remains atomically smooth after high temperature 7500C annealing, with the roughness measured to be about 0.5 nm by x-ray reflectivity (Fig. 9). In summary, remarkable device performance and material properties have been obtained in the GaN MOSFETs and MOSCAP employing high K A1203 dielectrics. The results from this work have demonstrated that the invers...