High-k dielectrics on (100) and (110) n-InAs: Physical and electrical characterizations

Abstract

Two high-k dielectric materials (Al2O3 and HfO2) were deposited on n-type (100) and (110) InAs surface orientations to investigate physical properties of the oxide/semiconductor interfaces and the interface trap density (Dit). X-ray photoelectron spectroscopy analyses (XPS) for native oxides of (100) and (110) as-grown n-InAs epi wafers show an increase in As-oxide on the (100) surface and an increase in InOx on the (110) surface. In addition, XPS analyses of high-k (Al2O3 and HfO2) on n-InAs epi show that the intrinsic native oxide difference between (100) and (110) epi surfaces were eliminated by applying conventional in-situ pre-treatment (TriMethyAluminium (TMA)) before the high-k deposition. The capacitance-voltage (C-V) characterization of HfO2 and Al2O3 MOSCAPs on both types of n-InAs surfaces shows very similar C-V curves. The interface trap density (Dit) profiles show Dit minima of 6.1 × 1012/6.5 × 1012 and 6.6 × 1012/7.3 × 1012 cm−2 eV−1 for Al2O3 and HfO2, respectively for (100) and (110) InAs surfaces. The similar interface trap density (Dit) on (100) and (110) surface orientation were observed, which is beneficial to future InAs FinFET device with both (100) and (110) surface channel orientations present.

Band offsets and trap-related electron transitions at interfaces of (100)InAs with atomic-layer deposited Al2O3

“…The obtained estimate of about 1 nm would agree with the width of the As distribution at the interface of InAs with an a-Al 2 O 3 layer grown under similar conditions as reported in Ref. 15 (cf. Fig.…”

“…7 Similarly, the InAs/Al 2 O 3 stack can be used to improve the electrical quality of GaSb p-type channels. [8][9][10] Most importantly, InAs is considered as a high mobility electron channel in a variety of transistor configurations ranging from planar metal-oxidesemiconductor (MOS) field-effect transistors (FETs) [11][12][13] to nano-wire FETs 14,15 and band-to-band tunneling devices. 16,17 The major difficulty in the realization of practically useful InAs-based transistors appears to be the poor electrical quality of interfaces with deposited oxide insulators.…”

Vertical Gate-All-Around Nanowire GaSb-InAs Core-Shell n-Type Tunnel FETs

“…A Gaussian D it distribution with peak at 1.4 × 10 13 cm −2 eV −1 centered at the InAs conduction band edge ( E c ) and at the high-k/InAs interface was included to account for defects in the device. This D it distribution is similar to experimentally obtained values for InAs with similar surface treatment prior to high-k deposition and high-k 19 . Other defects, such as traps at GaSb-InAs, GaSb-GaAs, or GaAs-InAs interface were not included as none were observed in TEM.…”

Structural and Electrical Properties of EOT HfO2 (<1 nm) Grown on InAs by Atomic Layer Deposition and Its Thermal Stability

“…As Si-based complementary metal oxide semiconductor (MOS) devices are being aggressively scaled down in the semiconductor industry, more elaborate gate stacks with sub-1 nm equivalent oxide thickness (EOT) gate dielectrics and high mobility channel materials with a low power consumption are required for use in MOS device applications. − In the next generation large scale integrations, Hf-based gate dielectrics (high-κ) on III–V compound semiconductors such as GaAs, InGaAs, and InAs are being seriously considered. − Among them, HfO 2 /InAs (bulk mobility ∼30 000 cm 2 V –1 s –1 ) shows high band offsets of over 2.0 eV, a high transconductance, high drive current at low voltages, and high-frequency operation, which are all very promising electrical properties for use in MOS devices. − However, it was reported that the electrical properties of HfO 2 /InAs are significantly affected by the crystalline structure of the high-κ dielectric layer and the surface orientation of the InAs substrate. − In addition, calculated electronic structure of the HfO 2 /InAs interface using density functional theory showed that interfacial defect states within InAs band gap are inevitably generated. , In particular, the elemental As states at the HfO 2 /InAs interface leads to the development of a large amount of midgap traps and oxide charge traps. Therefore, it is essential to develop a systematic understanding of the origin of the interfacial defect states in HfO 2 /InAs and to develop various defect control technique for further development.…”