Interface Characterization of HfO₂/GaSb MOS Capacitors With Ultrathin Equivalent Oxide Thickness by Using Hydrogen Plasma Treatment

Interface Optimization and Modulation of Leakage Current Conduction Mechanism of Yb2O3/GaSb MOS Capacitors with ALD-Driven Laminated Interlayers

“…This may be mainly attributed to a very low oxygen diffusion for Al 2 O 3 layers, which can effectively delay the interdiffusion between Yb 2 O 3 gate dielectrics and GaSb substrates. For S2 with Al 2 O 3 /Yb 2 O 3 /GaSb gate stacks, most of the Ga–Sb bonds have been transformed into the Ga–O bonding states, which can be explained by the accelerated oxidation of GaSb during direct deposition of the Yb 2 O 3 dielectric via the following reaction , …”

“…Consequently, as-received GaSb is characterized by high interface-state density ( D it ), which critically impedes the development of GaSb-based devices. Therefore, different passivation techniques on the GaSb surface have been intensively explored, including hydrogen plasma treatment, wet chemical processing, and sulfur and nitrogen passivations. , However, although these processes have significantly protected the substrate surface from further oxidation, it is still unrealistic due to the high interface-state density to make the incorporation of GaSb as an alternative channel material into silicon in a short time …”

Highly scaled equivalent oxide thickness of 0.66 nm for TiN/HfO2/GaSb MOS capacitors by using plasma-enhanced atomic layer deposition

“…9,[16][17][18] Because other literatures lack information regarding extracted flatband voltage, the gate leakage current was estimated at V g = ±1 V even though we understand, for a more accurate comparison, the gate leakage should be evaluated at V g = (V FB − 1 V) as done in this study and our previous literature. 9) An ultrathin EOT of 0.66 nm with a gate leakage current much less than 10 −8 A=µm 2 (suitable for high-performance applications) was successfully achieved. 19) Furthermore, a gate leakage current as low as 1.5 × 10 −10 A=µm 2 , which is essential for low-power devices, was realized.…”

“…4) Therefore, the performance of Sb-based materials with high hole mobility in p-type III-V alternate channel transistors must be determined. 4,5) Various high-κ materials, such as Al 2 O 3 , Y 2 O 3 , and HfO 2 , have been investigated, 1,6,7,[9][10][11][15][16][17] but the interface quality of high-κ dielectrics and GaSb is presently a severe challenge when using GaSb materials. Moreover, according to the logic core device technology roadmap in the 2015 ITRS, 4) channel capacitance is expected to increase to 40.61 fF=µm 2 in 2021, which means that the equivalent oxide thickness (EOT) should be scaled down to 0.8 nm.…”

“…These results showed that in situ HPT prior to the high-κ deposition can facilitate a more aggressive EOT scaling. The mechanism underlying the reduction of the native oxide has been well reported in the literature, [9][10][11] whereas only a few recent studies have discussed the etching phenomenon of the GaSb substrate. The inset in Fig.…”