HgCdTe Epitaxial Layer Surface Treatment Using Ammonium Sulfide Before Passivation

2019 ◽  
pp. 453-460
Author(s):  
Rachna Manchanda ◽  
Varun Sharma ◽  
Chanchal ◽  
V. K. Singh ◽  
Anshu Goyal ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Epitaxial Layer ◽  
Layer Surface ◽  
Ammonium Sulfide

Wide (0001) terrace formation due to step bunching on a vicinal 4H-SiC (0001) epitaxial layer surface

2017 ◽  
Vol 122 (7) ◽  
pp. 075702 ◽  
Author(s):  
Yuki Tabuchi ◽  
Koji Ashida ◽  
Masashi Sonoda ◽  
Tadaaki Kaneko ◽  
Noboru Ohtani ◽  
...  
Keyword(s):  
Epitaxial Layer ◽  
Layer Surface ◽  
Step Bunching

Control of the Surface Morphology on Low Off Angled 4H-SiC Homoepitaxal Growth

2009 ◽  
Vol 615-617 ◽  
pp. 113-116 ◽  
Author(s):  
Kazutoshi Kojima ◽  
Hajime Okumura ◽  
Kazuo Arai
Keyword(s):  
Surface Morphology ◽  
Epitaxial Growth ◽  
Epitaxial Layer ◽  
Flow Rate ◽  
Growth Conditions ◽  
Layer Surface ◽  
Specular Surface ◽  
Homoepitaxial Growth ◽  
Angle Difference ◽  
The Face

We have carried out detailed investigations on the influence of the growth conditions and the wafer off angle on the surface morphology of low off angle homoepitaxial growth. We found triangular features to be also serious problems on a 4 degree off 4H-SiC Si-face epitaxial layer surface. The control of the C/Si ratio by controlling the SiH4 flow rate is effective in suppressing the triangular features on 4 degree off Si-face homoepitaxial layer. As regards epitaxial growth on a vicinal off-axis substrate, the small off angle difference of a tenth part of a degree has an influence on the surface morphology of the epitaxial layer. This tendency depends on the face polarity and a C-face can be obtained that has a specular surface with a lower vicinal off angle than a Si-face. By controlling this off angle, a specular surface morphology without a bunched step structure could be obtained on a vicinal off angle 4H-SiC Si-face.

Influences of surface treatment on In0.53Ga0.47As epitaxial layer grown on silicon substrate using trimethylaluminum

2018 ◽  
Vol 646 ◽  
pp. 173-179
Author(s):  
Soo Bin Kim ◽  
Seung Hyun Lee ◽  
Hae Jun Jung ◽  
Myung Su Seo ◽  
Sung Min Kim ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Epitaxial Layer ◽  
Silicon Substrate

4H-SiC Epi-Ready Substrate Qualification by Using Mirror Electron Microscope Inspection System

2020 ◽  
Vol 1004 ◽  
pp. 369-375
Author(s):  
Masaki Hasegawa ◽  
Kentaro Ohira ◽  
Noriyuki Kaneoka ◽  
Tomohiko Ogata ◽  
Katsunori Onuki ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Epitaxial Layer ◽  
Basal Plane ◽  
Mechanical Polishing ◽  
Inspection System ◽  
Layer Surface ◽  
Discrete Point ◽  
Surface Polishing ◽  
Point Set ◽  
Crystal Damage

Crystal damage beneath the surface remaining after chemo-mechanical polishing (CMP) and basal plane dislocations (BPDs) of 4H-SiC epi-ready substrates have been inspected by using a mirror electron microscope inspection system non-destructively. Distributions of crystal damage and BPDs as well as their average densities are estimated by acquiring 80-μm square mirror electron images at positions distributed with an equal pitch over a substrate (“Discrete point set inspection”). Although the total inspected area is less than 1% of the entire substrate area, the inspection results for nine commercially available wafers reveal that there are large differences in surface polishing quality and BPD density between them. Evaluation on an epitaxial layer with a thickness of 10 μm grown on one of the inspected substrates indicated that correlation between distribution of the crystal damages on the substrate and that of bunched steps on the epitaxial layer surface.

High Quality Non-Alloyed Pt Ohmic Contacts to P-Type GaN Using Two-Step Surface Treatment

1999 ◽  
Vol 595 ◽  
Author(s):  
Ja-Soon Jang ◽  
Seong-Ju Park ◽  
Tae-Yeon Seong
Keyword(s):  
Surface Treatment ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Transport Mechanisms ◽  
High Quality ◽  
Ammonium Sulfide ◽  
Current Voltage ◽  
Specific Contact ◽  
Thermionic Field Emission ◽  
P Type

AbstractTwo-step surface-treatment is introduced to obtain low resistance Pt contacts to ptype GaN. The first step is performed after the mesa etching process using buffered oxide etch (BOE) and ammonium sulfide [(NH4)2Sx]. This is followed by the second step using BOE. The Pt contact, which was treated sequentially using ultrasonically boiled BOE (10 min) and boiled (NH4)2Sx (10 min), produces a specific contact resistance of 3.0 (±3.8)×10-5 Ωcm2. However, the contact, that was simply BOE-treated, yields 3.1 (±1.1)×10-2 Ωcm2. This indicates that the two-step surface treatment is promising technique for obtaining high quality ohmic contacts to p-GaN. Investigation of the electronic transport mechanisms using current-voltage-temperature (I-V-T) data indicates that thermionic field emission is dominant in the surface-treated Pt contacts.

scholarly journals Surface Modification on the Sputtering-Deposited ZnO Layer for ZnO-Based Schottky Diode

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Ren-Hao Chang ◽  
Kai-Chao Yang ◽  
Tai-Hong Chen ◽  
Li-Wen Lai ◽  
Tsung-Hsin Lee ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Schottky Diode ◽  
Ohmic Contact ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Layer Surface ◽  
Barrier Heights ◽  
Ammonium Sulfide ◽  
Current Voltage ◽  
Contact Electrode

We prepare a zinc oxide- (ZnO-) based Schottky diode constructed from the transparent cosputtered indium tin oxide- (ITO-) ZnO ohmic contact electrode and Ni/Au Schottky metal. After optimizing the ohmic contact property and removing the ion-bombardment damages using dilute HCl etching solution, the dilute hydrogen peroxide (H2O2) and ammonium sulfide (NH4)2Sxsolutions, respectively, are employed to modify the undoped ZnO layer surface. Both of the Schottky barrier heights with the ZnO layer surface treated by these two solutions, evaluated from the current-voltage (I-V) and capacitance-voltage (C-V) measurements, are remarkably enhanced as compared to the untreated ZnO-based Schottky diode. Through the X-ray photoelectron spectroscopy (XPS) and room-temperature photoluminescence (RTPL) investigations, the compensation effect as evidence of the increases in the O–H and OZnacceptor defects appearing on the ZnO layer surface after treating by the dilute H2O2solution is responsible for the improvement of the ZnO-based Schottky diode. By contrast, the enhancement on the Schottky barrier height for the ZnO layer surface treated by using dilute (NH4)2Sxsolution is attributed to both the passivation and compensation effects originating from the formation of the Zn–S chemical bond andVZnacceptors.

A quantitative model of epitaxial layers growth from the gas phase with a simultaneous participation of diffusion, adsorption, and chemical reaction

1986 ◽  
Vol 51 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Emerich Erdös ◽  
Jiří Laitner ◽  
Josef Stejskal ◽  
Přemysl Klíma
Keyword(s):  
Growth Rate ◽  
Gas Phase ◽  
Epitaxial Layer ◽  
Chemical Nature ◽  
Quantitative Description ◽  
Physical Nature ◽  
Rate Equations ◽  
Layer Surface ◽  
Active Centre ◽  
Rate Controlling Step

For a quantitative description of the epitaxial growth rate of gallium arsenide, a model has been proposed including two rate controlling steps, namely one step of physical nature and the other one of chemical nature. As the step of physical nature, the diffusion of gaseous components between the gas phase and the epitaxial layer surface has been considered, and from the steps of chemical nature the adsorption of gaseous components on the epitaxial layer surface and a heterogenous surface reaction have been taken into account. According to the kind of the chemical rate controlling step, five mechanisms have been proposed, where a one - centre model was used in all cases, i.e. the idea that the rate controlling step takes place under participation of one active centre. For all the mechanisms considered, the pertaining rate equations have been derived, which were confronted with the experimentally found dependences of the growth rate on partial pressures of components in the feed. The results are discussed both from the view point of plausibility of individual mechanisms and from the point of view of their applicability and of the next research direction.

SEM and ECC Imaging Study of Step-Bunched Structure on 4H-SiC Epitaxial Layers

2017 ◽  
Vol 897 ◽  
pp. 205-208
Author(s):  
Yuki Tabuchi ◽  
Masashi Sonoda ◽  
Koji Ashida ◽  
Tadaaki Kaneko ◽  
Noboru Ohtani ◽  
...  
Keyword(s):  
Epitaxial Layer ◽  
Formation Mechanism ◽  
Low Voltage ◽  
Imaging Study ◽  
Layer Surface ◽  
Step Bunching ◽  
Electron Channeling ◽  
Voltage Electron ◽  
Electron Scanning Microscopy ◽  
Atomically Flat

Step bunching on a vicinal 4H-SiC (0001) epitaxial layer surface was investigated using low-voltage electron scanning microscopy (LVSEM) and electron channeling contrast (ECC) imaging. LVSEM observations revealed that the step bunching resulted in the formation of atomically flat wide (~250 nm) terraces on the surface, and the terraces tended to form in pairs. The two terraces in paired terraces often showed the same electron channeling contrast as each other, and the contrast of the two terraces, either bright or dark, appeared to be determined by the orthogonal misorientation of substrates. On the basis of these results, the formation mechanism of the step-bunched structure on a vicinal 4H-SiC (0001) surface is discussed.

scholarly journals Study of Ammonium Sulfide Surface Treatment for Ultrathin Cu(In,Ga)Se 2 with Different Cu/(Ga + In) Ratios

2020 ◽  
Vol 217 (19) ◽  
pp. 2000307
Author(s):  
Dilara Gokcen Buldu ◽  
Jessica de Wild ◽  
Thierry Kohl ◽  
Guy Brammertz ◽  
Gizem Birant ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Ammonium Sulfide

Monitoring of Substrate and Epilayer Surfaces by Mirror Projection Electron Microscope

2019 ◽  
Vol 963 ◽  
pp. 255-258
Author(s):  
Isaho Kamata ◽  
Kentaro Ohira ◽  
Kenji Kobayashi ◽  
Masaki Hasegawa ◽  
Mitsuyasu Miyata ◽  
...  
Keyword(s):  
Epitaxial Layer ◽  
Flow Direction ◽  
Substrate Surface ◽  
Surface Damage ◽  
Layer Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Surface Damages ◽  
The Relationship

4H-SiC surfaces before and after epitaxial growth (substrate and epitaxial layer surfaces) were investigated by mirror projection electron microscopy (MPJ) and atomic force microscopy (AFM). On the epitaxial layer surface, two types of short-step-bunchings (SSBs) were observed, one of which featured double grooves and protrusion perpendicular to the step-flow direction and the other, a single groove and protrusion. We also investigated the substrate surface and detected features of sub-surface damage and dislocations. These surfaces were compared and the relationship between the SSBs on the epitaxial layer surface and sub-surface damages and dislocations on the substrate surface were discussed.

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