Impact of Interface Defect Passivation on Conduction Band Offset at SiO2/4H-SiC Interface

2012 ◽  
Vol 717-720 ◽  
pp. 721-724 ◽  
Author(s):  
Takuji Hosoi ◽  
Takashi Kirino ◽  
Atthawut Chanthaphan ◽  
Yusuke Uenishi ◽  
Daisuke Ikeguchi ◽  
...  
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Hydrogen Gas ◽  
Band Alignment ◽  
Band Offset ◽  
Partial Recovery ◽  
Conduction Band Offset ◽  
Interface Defect ◽  
Defect Passivation ◽  
Thermally Grown

The change in energy band alignment of thermally grown SiO2/4H-SiC(0001) structures due to an interface defect passivation treatment was investigated by means of synchrotron radiation photoelectron spectroscopy (SR-PES) and electrical characterization. Although both negative fixed charge and interface state density in SiO2/SiC structures were effectively reduced by high-temparature hydrogen gas annealing (FGA), the conduction band offset (ΔEc) at the SiO2/SiC interface was found to be decreased by about 0.1 eV after FGA. In addition, a subsequent vacuum annealing to induce hydrogen desorption from the interface resulted in not only a slight degradation in interface property but also a partial recovery of ΔEc value. These results indicate that the hydrogen passivation of negatively charged defects near the thermally grown SiO2/SiC interface causes the reduction in conduction band offset. Therefore, the tradeoff between interface quality and conduction band offset for thermally grown SiO2/SiC MOS structure needs to be considered for developing SiC MOS devices.

Experimental and First-Principles Studies of the Band Alignment at the HfO2/4H-SiC (0001) Interface

2006 ◽  
Vol 527-529 ◽  
pp. 1071-1074 ◽  
Author(s):  
Carey M. Tanner ◽  
Jong Woo Choi ◽  
Jane P. Chang
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Density Functional ◽  
Atomic Layer ◽  
Band Alignment ◽  
Functional Theory ◽  
X Ray ◽  
Conduction Band Offset ◽  
Mos Devices ◽  
Layer Deposition

The electronic properties of HfO2 films on 4H-SiC were investigated to determine their suitability as high-κ dielectrics in SiC power MOS devices. The band alignment at the HfO2/4HSiC interface was determined by X-ray photoelectron spectroscopy (XPS) and supported by density functional theory (DFT) calculations. For the experimental study, HfO2 films were deposited on ntype 4H-SiC by atomic layer deposition (ALD). XPS analysis yielded valence and conduction band offsets of 1.69 eV and 0.75 eV, respectively. DFT predictions based on two monoclinic HfO2/4HSiC (0001) structures agree well with this result. The small conduction band offset suggests the potential need for further interface engineering and/or a buffer layer to minimize electron injection into the gate oxide.

Large conduction band offset at SiO2 /β-Ga2 O3 heterojunction determined by X-ray photoelectron spectroscopy

2016 ◽  
Vol 253 (4) ◽  
pp. 623-625 ◽  
Author(s):  
Keita Konishi ◽  
Takafumi Kamimura ◽  
Man Hoi Wong ◽  
Kohei Sasaki ◽  
Akito Kuramata ◽  
...  
Keyword(s):  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Band Offset ◽  
X Ray ◽  
Conduction Band Offset

Band alignment at amorphous/crystalline silicon hetero-interfaces

2011 ◽  
Vol 1321 ◽  
Author(s):  
L. Korte ◽  
T. F. Schulze ◽  
C. Leendertz ◽  
M. Schmidt ◽  
B. Rech
Keyword(s):  
Photoelectron Spectroscopy ◽  
Experimental Error ◽  
Crystalline Silicon ◽  
Band Alignment ◽  
Low Energy ◽  
Surface Photovoltage ◽  
Band Offset ◽  
Conduction Band Offset ◽  
Silicon Heterojunctions ◽  
Deposition Conditions

ABSTRACTWe present an investigation of the band offsets in amorphous/crystalline silicon heterojunctions (a-Si:H/c-Si) using low energy photoelectron spectroscopy, ellipsometry and surface photovoltage data. For a variation of deposition conditions that lead to changes in hydrogen content and the thereby the a-Si:H band gap by ∼180 meV, we find that mainly the conduction band offset ΔEV varies, while ΔEC stays constant within experimental error. This result can be understood in the framework of charge neutrality (CNL) band lineup theory.

Electronic Properties of GaN (0001) – Dielectric Interfaces

2004 ◽  
Vol 14 (01) ◽  
pp. 107-125 ◽  
Author(s):  
T. E. Cook ◽  
C. C. Fulton ◽  
W. J. Mecouch ◽  
R. F. Davis ◽  
G. Lucovsky ◽  
...  
Keyword(s):  
Electron Affinity ◽  
Photoelectron Spectroscopy ◽  
Band Alignment ◽  
Band Offset ◽  
Energy Bands ◽  
Interface Dipole ◽  
Conduction Band Offset ◽  
Dielectric Interfaces ◽  
P Type ◽  
Interface Type

The characteristics of clean n- and p-type GaN (0001) surfaces and the interface between this surface and SiO 2, Si 3 N 4, and HfO 2 have been investigated. Layers of SiO 2, Si3 N 4, or HfO 2 were carefully deposited to limit the reaction between the film and clean GaN surfaces. After stepwise deposition, the electronic states were measured with x-ray photoelectron spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS). A valence band offset (VBO) of 2.0±0.2 eV with a conduction band offset (CBO) of 3.6±0.2 eV was determined for the GaN / SiO 2 interface. The large band offsets suggest SiO 2 is an excellent candidate for passivation of GaN . For the GaN / Si 3 N 4, interface, type II band alignment was observed with a VBO of -0.5±0.2 eV and a CBO of 2.4±0.2 eV . While Si3 N 4 should passivate n-type GaN surfaces, it may not be appropriate for p-type GaN surfaces. A VBO of 0.3±0.2 eV with a CBO of 2.1±0.2 eV was determined for the annealed GaN / HfO 2 interface. An instability was observed in the HfO 2 film, with energy bands shifting ~0.4 eV during a 650°C densification anneal. The electron affinity measurements via UPS were 3.0, 1.1, 1.8, and 2.9±0.1 eV for GaN , SiO 2, Si 3 N 4, and HfO 2 surfaces, respectively. The deduced band alignments were compared to the predictions of the electron affinity model and deviations were attributed to a change of the interface dipole. Interface dipoles contributed 1.6, 1.1 and 2.0±0.2 eV to the band alignment of the GaN / SiO 2, GaN / Si 3 N 4, and GaN / HfO 2 interfaces, respectively. It was noted that the existence of Ga-O bonding at the heterojunction could significantly affect the interface dipole, and consequently the band alignment in relation to the GaN .

Band Alignment of CdS/Cu2ZnSnSe4 Heterointerface and Solar Cell Performances

MRS Advances ◽  
2017 ◽  
Vol 2 (53) ◽  
pp. 3157-3162 ◽  
Author(s):  
Takehiko Nagai ◽  
Shinho Kim ◽  
Hitoshi Tampo ◽  
Kang Min Kim ◽  
Hajime Shibata ◽  
...  
Keyword(s):  
Conduction Band ◽  
Band Alignment ◽  
Photoemission Spectroscopy ◽  
Band Offset ◽  
Valence Band Offset ◽  
X Ray ◽  
Heterojunction Solar Cells ◽  
Conduction Band Offset ◽  
Ultraviolet Photoemission Spectroscopy ◽  
Large Spike

ABSTRACTWe determined that the conduction band offset (CBO) and the valence band offset (VBO) at the CdS/ Cu2ZnSnSe4 (CZTSe) heterointerface are +0.56 and +0.89eV, respectively, by using X-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS) and inversed photoemission spectroscopy (IPES). A positive CBO value, so-called “spike” structure, means that the position of conduction band becomes higher than that of absorber layer. The evaluated CBO of +0.56 eV suggests that the conduction band alignment at CdS/CZTSe interface is enough to become an electron barrier. Despite such a large spike structure in the conduction band at the interface, a conversion efficiency of 8.7 % could be obtained for the CdS/CZTSe heterojunction solar cells.

scholarly journals Analytical study of effect of energy band parameters and lattice temperature on conduction band offset in AlN/Ga2O3 HEMT

2021 ◽  
Vol 34 (3) ◽  
pp. 323-332
Author(s):  
Rajan Singh ◽  
Trupti Lenka ◽  
Hieu Nguyen
Keyword(s):  
Schottky Barrier ◽  
Conduction Band ◽  
Energy Band ◽  
Analytical Study ◽  
Band Alignment ◽  
Lattice Temperature ◽  
Band Offset ◽  
Conduction Band Offset ◽  
Energy Bandgap ◽  
2Deg Density

Apart from other factors, band alignment led conduction band offset (CBO) largely affects the two dimensional electron gas (2DEG) density ns in wide bandgap semiconductor based high electron mobility transistors (HEMTs). In the context of assessing various performance metrics of HEMTs, rational estimation of CBO and maximum achievable 2DEG density is critical. Here, we present an analytical study on the effect of different energy band parameters-energy bandgap and electron affinity of heterostructure constituents, and lattice temperature on CBO and estimated 2DEG density in quantum triangular-well. It is found that at thermal equilibrium, ns increases linearly with ?EC at a fixed Schottky barrier potential, but decreases linearly with increasing gate-metal work function even at fixed ?EC, due to increased Schottky barrier heights. Furthermore, it is also observed that poor thermal conductivity led to higher lattice temperature which results in lower energy bandgap, and hence affects ?EC and ns at higher output currents.

Chemical Composition and Electronic Properties of CuInS2/Zn(S,O) Interfaces

2009 ◽  
Vol 1165 ◽  
Author(s):  
Rodrigo Sáez-Araoz ◽  
Iver Lauermann ◽  
Axel Neisser ◽  
Martha Ch Lux-Steiner ◽  
Ahmed Ennaoui
Keyword(s):  
Chemical Composition ◽  
Band Gap ◽  
Conduction Band ◽  
Photoelectron Spectroscopy ◽  
Energy Band ◽  
Band Offset ◽  
Energy Band Gap ◽  
Valence Band Offset ◽  
X Ray ◽  
Conduction Band Offset

AbstractWe report on the chemical deposition and electronic properties of CuInS2/Zn(S,O) interfaces. The Zn(S,O) buffer was grown by a new chemical bath deposition (CBD) process that allows the tailoring of the S/O ratio in the films. Resulting Zn(S,O) films exhibit transparencies above 80% (for λ>390 nm) and an optical energy band gap of 3.9 eV which decreases to 3.6 eV after annealing in air at 200°C. Production line CuInS2 (CIS) absorbers provided by Sulfurcell Solartechnik GmbH are used as substrates for the investigation of the CIS/Zn(S,O) interface and the chemical composition of Zn(S,O). A ZnS/(ZnS+ZnO) ratio of 0.5 is found by X-ray photoelectron spectroscopy and X-ray excited Auger electron spectroscopy (XPS and XAES). The valence band offset between the heterojunction partners (ΔEV = 1.8 ± 0.2 eV) has been determined by means of XPS and ultraviolet photoelectron spectroscopy (UPS). Considering the energy band gap of the CIS absorber and the measured band gap of Zn(S,O), the conduction band offset (ΔEC) is calculated as: resulting in a spike of 0.5±0.3 eV in the conduction band at the heterojunction before annealing. After the heat treatment, the valence band offset is reduced to 1.5±0.2 eV and the calculated conduction band offset remains at 0.5±0.3 eV.

Effects of Post-Deposition Annealing Temperature on Band Alignment and Electrical Characteristics of Lanthanum Cerium Oxide on 4H-SiC

2012 ◽  
Vol 1433 ◽  
Author(s):  
Way F. Lim ◽  
Kuan Y. Cheong
Keyword(s):  
Conduction Band ◽  
Annealing Temperature ◽  
Band Alignment ◽  
Trap Density ◽  
Band Offset ◽  
Interface Trap Density ◽  
Interface Trap ◽  
Post Deposition Annealing ◽  
Conduction Band Offset ◽  
Post Deposition

ABSTRACTInvestigation of lanthanum cerium oxide as a gate oxide on 4H-SiC was performed by varying post-deposition annealing temperature from 400 to 1000°C. Energy band alignment and band gap of bulk oxide and interfacial layer (IL) with respect to SiC were extracted using X-ray photoelectron microscopy. Two band alignment structures were proposed and the change of band alignment was affected by the changes in chemical composition in bulk oxide and in IL that may induce lattice strains and dipoles. A conduction band offset of IL/SiC was 0.97 eV for sample annealed at 1000°C, which was comparable to the value extracted from Fowler-Nordheim model. The acquisition of sufficient conduction band offset, coupled with the lowest slow trap density, effective oxide charges, interface trap density, as well as total interface trap density, yielded the lowest leakage current density for this sample.

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