| Records |
| Author |
Vohra, A.; Khanam, A.; Slotte, J.; Makkonen, I.; Pourtois, G.; Loo, R.; Vandervorst, W. |
| Title |
Evolution of phosphorus-vacancy clusters in epitaxial germanium |
Type |
A1 Journal article |
| Year |
2019 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
| Volume |
125 |
Issue |
2 |
Pages |
025701 |
| Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
The E centers (dopant-vacancy pairs) play a significant role in dopant deactivation in semiconductors. In order to gain insight into dopant-defect interactions during epitaxial growth of in situ phosphorus doped Ge, positron annihilation spectroscopy, which is sensitive to open-volume defects, was performed on Ge layers grown by chemical vapor deposition with different concentrations of phosphorus (similar to 1 x 10(18)-1 x 10(20) cm(-3)). Experimental results supported by first-principles calculations based on the two component density-functional theory gave evidence for the existence of mono-vacancies decorated by several phosphorus atoms as the dominant defect type in the epitaxial Ge. The concentration of vacancies increases with the amount of P-doping. The number of P atoms around the vacancy also increases, depending on the P concentration. The evolution of P-n-V clusters in Ge contributes significantly to the dopant deactivation. Published under license by AIP Publishing. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
|
Editor |
|
| Language |
|
Wos |
000455922100057 |
Publication Date |
2019-01-08 |
| Series Editor |
|
Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0021-8979; 1089-7550 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.068 |
Times cited |
5 |
Open Access  |
Not_Open_Access |
| Notes |
|
Approved |
Most recent IF: 2.068 |
| Call Number |
UA @ admin @ c:irua:156722 |
Serial |
5274 |
| Permanent link to this record |
| |
|
| |
| Author |
Dhayalan, S.K.; Nuytten, T.; Pourtois, G.; Simoen, E.; Pezzoli, F.; Cinquanta, E.; Bonera, E.; Loo, R.; Rosseel, E.; Hikavyy, A.; Shimura, Y.; Vandervorst, W. |
| Title |
Insights into the C Distribution in Si:C/Si:C:P and the Annealing Behavior of Si:C Layers |
Type |
A1 Journal article |
| Year |
2019 |
Publication |
ECS journal of solid state science and technology |
Abbreviated Journal |
Ecs J Solid State Sc |
| Volume |
8 |
Issue |
4 |
Pages |
P209-P216 |
| Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
Si:C and Si:C:P alloys are potential candidates for source-drain stressor applications in n-type Fin Field Effect Transistors (FinFETs). Increasing the C content to achieve high strain results in the arrangement of C atoms as third nearest neighbors (3nn) in the Si: C lattice. During thermal annealing, the presence of C atoms as 3nn may promote clustering at the interstitial sites, causing loss of stress. The concentration of C atoms as 3nn is reduced by the incorporation of a small amount of Ge atoms during the growth, whereas in-situ P doping does not influence this 3nn distribution [J Solid State Sci. Technol vol 6, p 755, 2017]. Small amounts of Ge are provided during low temperature selective epitaxial growth scheme, which are based on cyclic deposition and etching (CDE). In this work, we aim to provide physical insights into the aforementioned phenomena, to understand the behavior of 3nn C atoms and the types of defects that are formed in the annealed Si: C films. Using ab-initio simulations, the Ge-C interaction in the Si matrix is investigated and this insight is used to explain how the Ge incorporation leads to a reduced 3nn distribution of the C atoms. The interaction between C and P in the Si: C: P films is also investigated to explain why the P incorporation has not led to a reduction in the 3nn distribution. We then report on the Raman characterization of Si: C layers subjected to post epi annealing. As the penetration depth of the laser is dependent on the wavelength, Raman measurements at two different wavelengths enable us to probe the depth distribution of 3nn C atoms after applying different annealing conditions. We observed a homogeneous loss in 3nn C throughout the layer. Whereas in the kinematic modeling of high resolution X-ray diffraction spectra, a gradient in the substitutional C loss was observed close to the epitaxial layer/substrate interface. This gradient can be due to the out diffusion of C atoms into the Si substrate or to the formation of interstitial C clusters, which cannot be distinguished in HR-XRD. Deep Level Transient Spectroscopy indicated that the prominent out-diffusing species was interstitial CO complex while the interstitial C defects were also prevalent in the epi layer. (c) 2019 The Electrochemical Society. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
|
Wos |
000465069200001 |
Publication Date |
2019-04-18 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2162-8769; 2162-8777 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
| Impact Factor |
1.787 |
Times cited |
|
Open Access |
Not_Open_Access |
| Notes |
|
Approved |
Most recent IF: 1.787 |
| Call Number |
UA @ admin @ c:irua:160399 |
Serial |
5275 |
| Permanent link to this record |
| |
|
| |
| Author |
Lu, A.K.A.; Houssa, M.; Luisier, M.; Pourtois, G. |
| Title |
Impact of layer alignment on the behavior of MoS2-ZrS2 tunnel field-effect transistors : an ab initio study |
Type |
A1 Journal article |
| Year |
2017 |
Publication |
Physical review applied |
Abbreviated Journal |
Phys Rev Appl |
| Volume |
8 |
Issue |
3 |
Pages |
034017 |
| Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
Tunnel field-effect transistors based on van der Waals heterostructures are emerging device concepts for low-power applications, auguring sub-60 mV/dec subthreshold swing values. In these devices, the channel is built from a stack of several different two-dimensional materials whose nature allows tailoring the band alignments and enables a good electrostatic control of the device. In this work, we propose a theoretical study of the variability of the performances of a MoS2-ZrS2 tunnel field-effect transistor induced by fluctuations of the relative position or the orientation of the layers. Our results indicate that although a steep subthreshold slope (20 mV/dec) is achievable, fluctuations in the relative orientation of the ZrS2 layer with respect to the MoS2 one lead to a significant variability in the tunneling current by about one decade. This arises from changes in the orbital overlap between the layers and from the modulation of the transport direction. |
| Address |
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| Corporate Author |
|
Thesis |
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| Publisher |
American Physical Society |
Place of Publication |
College Park, Md |
Editor |
|
| Language |
|
Wos |
000411460400001 |
Publication Date |
2017-09-22 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2331-7019 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
4.808 |
Times cited |
6 |
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 4.808 |
| Call Number |
UA @ lucian @ c:irua:146741 |
Serial |
4785 |
| Permanent link to this record |
| |
|
| |
| Author |
Loo, R.; Arimura, H.; Cott, D.; Witters, L.; Pourtois, G.; Schulze, A.; Douhard, B.; Vanherle, W.; Eneman, G.; Richard, O.; Favia, P.; Mitard, J.; Mocuta, D.; Langer, R.; Collaert, N. |
| Title |
Epitaxial CVD Growth of Ultra-Thin Si Passivation Layers on Strained Ge Fin Structures |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
ECS journal of solid state science and technology |
Abbreviated Journal |
Ecs J Solid State Sc |
| Volume |
7 |
Issue |
2 |
Pages |
P66-P72 |
| Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
Epitaxially grown ultra-thin Si layers are often used to passivate Ge surfaces in the high-k gate module of (strained) Ge FinFET and Gate All Around devices. We use Si4H10 as Si precursor as it enables epitaxial Si growth at temperatures down to 330 degrees. C-V characteristics of blanket capacitors made on Ge virtual substrates point to the presence of an optimal Si thickness. In case of compressively strained Ge fin structures, the Si growth results in non-uniform and high strain levels in the strained Ge fin. These strain levels have been calculated for different shapes of the Ge fin and in function of the grown Si thickness. The high strain is the driving force for potential (unwanted) Ge surface reflow during Si deposition. The Ge surface reflow is strongly affected by the strength of the H-passivation during Si-capping and can be avoided by carefully selected process conditions. (C) The Author(s) 2018. Published by ECS. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
Electrochemical society |
Place of Publication |
Pennington (N.J.) |
Editor |
|
| Language |
|
Wos |
000425215200010 |
Publication Date |
2018-01-21 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2162-8769; 2162-8777 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.787 |
Times cited |
5 |
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 1.787 |
| Call Number |
UA @ lucian @ c:irua:149326 |
Serial |
4933 |
| Permanent link to this record |
| |
|
| |
| Author |
de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P. |
| Title |
Method to quantify the delocalization of electronic states in amorphous semiconductors and its application to assessing charge carrier mobility of p-type amorphous oxide semiconductors |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
| Volume |
97 |
Issue |
4 |
Pages |
045208 |
| Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
Amorphous semiconductors are usually characterized by a low charge carrier mobility, essentially related to their lack of long-range order. The development of such material with higher charge carrier mobility is hence challenging. Part of the issue comes from the difficulty encountered by first-principles simulations to evaluate concepts such as the electron effective mass for disordered systems since the absence of periodicity induced by the disorder precludes the use of common concepts derived from condensed matter physics. In this paper, we propose a methodology based on first-principles simulations that partially solves this problem, by quantifying the degree of delocalization of a wave function and of the connectivity between the atomic sites within this electronic state. We validate the robustness of the proposed formalism on crystalline and molecular systems and extend the insights gained to disordered/amorphous InGaZnO4 and Si. We also explore the properties of p-type oxide semiconductor candidates recently reported to have a low effective mass in their crystalline phases [G. Hautier et al., Nat. Commun. 4, 2292 (2013)]. Although in their amorphous phase none of the candidates present a valence band with delocalization properties matching those found in the conduction band of amorphous InGaZnO4, three of the seven analyzed materials show some potential. The most promising candidate, K2Sn2O3, is expected to possess in its amorphous phase a slightly higher hole mobility than the electron mobility in amorphous silicon. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
American Physical Society |
Place of Publication |
New York, N.Y |
Editor |
|
| Language |
|
Wos |
000423427600005 |
Publication Date |
2018-01-25 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2469-9969; 2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
3.836 |
Times cited |
2 |
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 3.836 |
| Call Number |
UA @ lucian @ c:irua:149318 |
Serial |
4943 |
| Permanent link to this record |
| |
|
| |
| Author |
de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P. |
| Title |
Defects in amorphous semiconductors : the case of amorphous indium gallium zinc oxide |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
Physical review applied |
Abbreviated Journal |
Phys Rev Appl |
| Volume |
9 |
Issue |
9 |
Pages |
054039 |
| Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
Based on a rational classification of defects in amorphous materials, we propose a simplified model to describe intrinsic defects and hydrogen impurities in amorphous indium gallium zinc oxide (a-IGZO). The proposed approach consists of organizing defects into two categories: point defects, generating structural anomalies such as metal-metal or oxygen-oxygen bonds, and defects emerging from changes in the material stoichiometry, such as vacancies and interstitial atoms. Based on first-principles simulations, it is argued that the defects originating from the second group always act as perfect donors or perfect acceptors. This classification simplifies and rationalizes the nature of defects in amorphous phases. In a-IGZO, the most important point defects are metal-metal bonds (or small metal clusters) and peroxides (O-O single bonds). Electrons are captured by metal-metal bonds and released by the formation of peroxides. The presence of hydrogen can lead to two additional types of defects: metal-hydrogen defects, acting as acceptors, and oxygen-hydrogen defects, acting as donors. The impact of these defects is linked to different instabilities observed in a-IGZO. Specifically, the diffusion of hydrogen and oxygen is connected to positive-and negative-bias stresses, while negative-bias illumination stress originates from the formation of peroxides. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
American Physical Society |
Place of Publication |
College Park, Md |
Editor |
|
| Language |
|
Wos |
000433070900003 |
Publication Date |
2018-05-25 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2331-7019 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
4.808 |
Times cited |
7 |
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 4.808 |
| Call Number |
UA @ lucian @ c:irua:151497 |
Serial |
5019 |
| Permanent link to this record |
| |
|
| |
| Author |
de de Meux, A.J.; Pourtois, G.; Genoe, J.; Heremans, P. |
| Title |
Effects of hole self-trapping by polarons on transport and negative bias illumination stress in amorphous-IGZO |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
| Volume |
123 |
Issue |
16 |
Pages |
161513 |
| Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
The effects of hole injection in amorphous indium-gallium-zinc-oxide (a-IGZO) are analyzed by means of first-principles calculations. The injection of holes in the valence band tail states leads to their capture as a polaron, with high self-trapping energies (from 0.44 to 1.15 eV). Once formed, they mediate the formation of peroxides and remain localized close to the hole injection source due to the presence of a large diffusion energy barrier (of at least 0.6 eV). Their diffusion mechanism can be mediated by the presence of hydrogen. The capture of these holes is correlated with the low off-current observed for a-IGZO transistors, as well as with the difficulty to obtain a p-type conductivity. The results further support the formation of peroxides as being the root cause of Negative Bias Illumination Stress (NBIS). The strong self-trapping substantially reduces the injection of holes from the contact and limits the creation of peroxides from a direct hole injection. In the presence of light, the concentration of holes substantially rises and mediates the creation of peroxides, responsible for NBIS. Published by AIP Publishing. |
| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
Amer inst physics |
Place of Publication |
Melville |
Editor |
|
| Language |
|
Wos |
000431147200043 |
Publication Date |
2017-10-19 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
0021-8979; 1089-7550 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
2.068 |
Times cited |
4 |
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 2.068 |
| Call Number |
UA @ lucian @ c:irua:151570 |
Serial |
5021 |
| Permanent link to this record |
| |
|
| |
| Author |
Dhayalan, S.K.; Kujala, J.; Slotte, J.; Pourtois, G.; Simoen, E.; Rosseel, E.; Hikavyy, A.; Shimura, Y.; Loo, R.; Vandervorst, W. |
| Title |
On the evolution of strain and electrical properties in as-grown and annealed Si:P epitaxial films for source-drain stressor applications |
Type |
A1 Journal article |
| Year |
2018 |
Publication |
ECS journal of solid state science and technology |
Abbreviated Journal |
Ecs J Solid State Sc |
| Volume |
7 |
Issue |
5 |
Pages |
P228-P237 |
| Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
| Abstract |
Heavily P doped Si:P epitaxial layers have gained interest in recent times as a promising source-drain stressor material for n type FinFETs (Fin Field Effect Transistors). They are touted to provide excellent conductivity as well as tensile strain. Although the as-grown layers do provide tensile strain, their conductivity exhibits an unfavorable behavior. It reduces with increasing P concentration (P > 1E21 at/cm(3)), accompanied by a saturation in the active carrier concentration. Subjecting the layers to laser annealing increases the conductivity and activates a fraction of P atoms. However, there is also a concurrent reduction in tensile strain (<1%). Literature proposes the formation of local semiconducting Si3P4 complexes to explain the observed behaviors in Si:P [Z. Ye et al., ECS Trans., 50(9) 2013, p. 1007-10111. The development of tensile strain and the saturation in active carrier is attributed to the presence of local complexes while their dispersal on annealing is attributed to strain reduction and increase in active carrier density. However, the existence of such local complexes is not proven and a fundamental void exists in understanding the structure-property correlation in Si:P films. In this respect, our work investigates the reason behind the evolution of strain and electrical properties in the as-grown and annealed Si:P epitaxial layers using ab-initio techniques and corroborate the results with physical characterization techniques. It will be shown that the strain developed in Si:P films is not due to any specific complexes while the formation of Phosphorus-vacancy complexes will be shown responsible for the carrier saturation and the increase in resistivity in the as-grown films. Interstitial/precipitate formation is suggested to be a reason for the strain loss in the annealed films. (C) The Author(s) 2018. Published by ECS. |
| Address |
|
| Corporate Author |
|
Thesis |
|
| Publisher |
Electrochemical society |
Place of Publication |
Pennington (N.J.) |
Editor |
|
| Language |
|
Wos |
000440834200010 |
Publication Date |
2018-05-01 |
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
2162-8769; 2162-8777 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
| Impact Factor |
1.787 |
Times cited |
4 |
Open Access |
OpenAccess |
| Notes |
|
Approved |
Most recent IF: 1.787 |
| Call Number |
UA @ lucian @ c:irua:153204 |
Serial |
5122 |
| Permanent link to this record |
