Oliver Skibitzki

Oliver Skibitzki
IHP | Institute for High Performance Microelectronics · Material Research

PhD

About

58
Publications
15,877
Reads
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433
Citations
Additional affiliations
December 2013 - present
IHP
Position
  • Project Manager
February 2009 - November 2013
IHP
Position
  • PhD Student
Education
September 2013 - November 2013
Brandenburgische Technische Universität Cottbus-Senftenberg
Field of study
  • Semiconductor physics
October 2002 - September 2008

Publications

Publications (58)
Article
To develop a III/V wide bandgap collector concept for future SiGe heterobipolar transistor performance increase, a heterostructure growth study of GaP on pseudomorphic 4° off-oriented Si0.8Ge0.2/Si(001) substrates was performed. For pseudomorphic GaP/Si0.8Ge0.2/Si(001) heterostructure growth, critical thickness of GaP on Si and maximum thermal budg...
Article
We report a detailed structure and defect characterization study on gallium phosphide (GaP) layers integrated on silicon (Si) (001) via silicon-germanium (SiGe) buffer layers. The presented approach uses an almost fully relaxed SiGe buffer heterostructure of only 400 nm thickness whose in-plane lattice constant is matched to GaP—not at room but at...
Article
In this work, we demonstrate the growth of Ge crystals and suspended continuous layers on Si(001) substrates deeply patterned in high aspect-ratio pillars. The material deposition was carried out in a commercial reduced-pressure chemical vapor deposition (RPCVD) reactor, thus extending the "vertical-heteroepitaxy" technique developed by using the p...
Article
We present the nanoheteroepitaxial growth of gallium arsenide (GaAs) on nano-patterned silicon (Si) (001) substrates fabricated using a CMOS technology compatible process. The selective growth of GaAs nano-crystals (NCs) was achieved at 570 °C by MOVPE. A detailed structure and defect characterization study of the grown nano-heterostructures was pe...
Article
The threading dislocation density (TDD) in plastically relaxed Ge/Si(001) heteroepitaxial films is commonly observed to decrease progressively with their thickness due to mutual annihilation. However, there exists a saturation limit, known as the geometrical limit, beyond which a further decrease of the TDD in the Ge film is hindered. Here, we show...
Article
This work investigates the role of threading dislocation densities (TDD) in the low density regime on the vertical transport in Si0.06Ge0.94 heterostructures integrated on Si(001). The use of unintentionally doped Si0.06Ge0.94 layers enables the study of the impact of grown-in threading dislocations (TD) without interaction with processing-induced...
Article
Label-free optical detection of biomolecules is currently limited by a lack of specificity rather than sensitivity. To exploit the much more characteristic refractive index dispersion in the mid-infrared (IR) regime, we have engineered three-dimensional IR-resonant silicon micropillar arrays (Si-MPAs) for protein sensing. By exploiting the unique h...
Article
Ge-on-Si plasmonics holds the promise for compact and low-cost solutions in the manipulation of THz radiation. We discuss here the plasmonic properties of doped Ge bow-tie antennas made with a low-point cost CMOS mainstream technology. These antennas display resonances between 500 and 700 GHz, probed by THz time domain spectroscopy. We show surface...
Article
To satisfy the continuous demand of ever smaller feature sizes, plasma etching technologies in microelectronics enable the fabrication of device structures in the nanometer range. To control these processes, real-time access to the structure’s dimensions is needed. We develop a special method of optical critical dimension metrology and evaluate the...
Article
Full-text available
Highly polar materials are usually preferred over weakly polar ones to study strong electron-phonon interactions and its fascinating properties. Here, we report on the achievement of simultaneous confinement of charge carriers and phonons at the vicinity of a 2D vertical homovalent singularity (antiphase boundary, (APB)) in an (In, Ga)P/SiGe/Si sam...
Article
Germanium (Ge) nanowires (NWs) were grown in-plane on nano-structured Si(001)/SiO2 substrates by molecular beam epitaxy using gold (Au) as the solvent. The site-selective NW growth was enabled by a rectangular array of gold droplets on silicon (Si) tips with an Au nuclei density below 0.25 μm−2 on the surrounding silicon oxide (SiO2). The initial g...
Article
Full-text available
We investigate the temperature dependence of the Ge Raman mode strain–phonon coefficient in Ge/Si heteroepitaxial layers. By analyzing the temperature‐dependent evolution of both the Raman Ge─Ge line and of the Ge lattice strain, we obtain a linear dependence of the strain–phonon coefficient as a function of temperature. Our findings provide an eff...
Article
Exploiting intersubband transitions in Ge/SiGe quantum cascade devices provides a way to integrate terahertz light emitters into silicon-based technology. With the view to realizing a Ge/SiGe Quantum Cascade Laser, we present the optical and structural properties of n-type strain-symmetrized Ge/SiGe asymmetric coupled quantum wells grown on Si(001)...
Article
The nondestructive detection and evaluation of crystallographic properties of nanocrystals is of great significance for both fundamental physics research and further development of high-performance functional devices employing nanostructured materials. Synchrotron radiation-based CXD using a nanoscale x-ray beam is shown to be a powerful tool to ex...
Poster
Full-text available
Theoretical predictions indicate that the n-type Ge/SiGe multi quantum-well system is the most promising material for the realization of a Si-compatible THz quantum cascade laser (QCL) operating at room temperature. As a key step forward for QCL design within the SiGe material platform, we studied both experimentally and theoretically asymmetric co...
Article
HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based solid-state incandescent light emission devices (SSI-LEDs) with conductive filament-related light emission mechanism are promising candidates for future light emission devices. In this letter, the temperature impact on the electrical an...
Article
Theoretical predictions indicate that the n-type Ge/Si−Ge multi-quantum-well system is the most promising material for the realization of a Si-compatible THz quantum cascade laser operating at room temperature. To advance in this direction, we study, both experimentally and theoretically, asymmetric coupled multi-quantum-well samples based on this...
Article
We investigate the distribution of Sn in GeSn nano-heteroepitaxial clusters deposited at temperatures well exceeding the eutectic temperature of the GeSn system. The 600°C molecular beam epitaxy on Si-patterned substrates results in the selective growth of GeSn nano-clusters having a 1.4 ± 0.5 at. % Sn content. These nanoclusters feature Sn droplet...
Article
We demonstrate a novel method for the stable and selective surface functionalization of germanium (Ge) embedded in silicon dioxide. The Ge(001) surface is functionalized using α-lipoic acid (ALA), which can potentially be utilized for the immobilization of a wide range of biomolecules. We present a detailed pH-dependence study to establish the effe...
Article
Full-text available
We present the morphological evolution obtained during the annealing of Ge strips grown on Si ridges as a prototypical process for 3D device architectures and nanophotonic applications. In particular, the morphological transition occurring from Ge/Si nanostrips to nanoislands is illustrated. The combined effect of performing annealing at different...
Article
The local atomic structure of [110] tilt grain boundaries (GBs) formed in ∼100 nm-sized GaAs nanocrystals, which crystallize in the non-centrosymmetric zincblende-type structure with face-centred cubic lattice symmetry, was imaged and analysed by means of high-resolution high-angle annular dark-field scanning transmission electron microscopy (HAADF...
Article
Full-text available
We report the observation of field emission from InP nanocrystals epitaxially grown on an array of p-Si nanotips. We prove that field emission can be enhanced by covering the InP nanocrystals with graphene. The measurements are performed inside a scanning electron microscope chamber with a nano-controlled W-thread used as an anode. We analyze the f...
Article
This study reports on a novel vacuum epitaxial lift-off (VELO) process to reuse the GaAs substrates in lightemitting diode (LED) production. The method is based on an epitaxial lift-off technique, whose application is however limited to flexible wafers, as gaseous reaction products (e.g. AsH3) formed during the etching of AlAs with hydrofluoric aci...
Article
Crystal defects, present in ~100 nm GaAs nanocrystals grown by metal organic vapour phase epitaxy on top of (0 0 1)-oriented Si nanotips (with a tip opening 50–90 nm), have been studied by means of high-resolution aberrationcorrected high-angle annular dark-field scanning transmission electron microscopy. The role of 60° perfect, 30° and 90° Shockl...
Article
Phosphide-based thin-film light-emitting diodes (TF-LEDs) lattice-matched to GaAs are well established in optoelectronics in the wavelength range between 550 and 650 nm. In this work, we investigate the impact of oxidizedAlAs to overlying phosphide-based pseudomorphically grownepitaxialstructures.Oxidation of a buried AlAs sacrificial layer allows...
Article
The early growth stage of GaAs by metal organic vapor phase epitaxy on a novel kind of Si substrate is investigated. The substrate consists of nanotips (NTs) fabricated on a Si(001) wafer by means of lithography and reactive ion etching. 3D GaAs nanocrystals are found to nucleate with a probability of 90% on the (n0m), (-n0m), (0nm), and (0-nm) fac...
Article
Nano-heteroepitaxial growth of GaAs on Si(001) by metal organic vapor phase epitaxy was investigated to study emerging materials phenomena on the nano-scale of III–V/Si interaction. Arrays of Si nano-tips (NTs) embedded in a SiO 2 matrix were used as substrates. The NTs had top Si openings of 50–90 nm serving as seeds for the selective growth of Ga...
Article
Full-text available
We demonstrate tunable Schottky barrier height and record photo-responsivity in a new-concept device made of a single-layer CVD graphene transferred onto a matrix of nanotips patterned on n-type Si wafer. The original layout, where nano-sized graphene/Si heterojunctions alternate to graphene areas exposed to the electric field of the Si substrate,...
Conference Paper
A novel strategy towards the scalable realization of site controlled III-V quantum dots on Si substrates is presented. The nano-heteroepitaxy of InAs/GaAs nanostructures on Si(001) nano-tips was evaluated by structural and optical characterization.
Conference Paper
The increasing demand for high-performance, ultra-small size electronics and photonics requires the development of new nanostructured materials. Promising candidates for this purpose are monolithically integrated GaAs nanocrystals, selectively grown by metal organic vapor phase epitaxy (MOVPE), on top of Si nano-tips and nano-pillars (Fig. 1,2) wit...
Article
In this letter, we explore in detail the potential of nanoheteroepitaxy to controllably fabricate high quality GeSn nano-structures and to further improve the crystallinity of GeSn alloys directly grown on Si(001). The GeSn was grown by molecular beam epitaxy at relatively high temperatures up to 750 °C on pre-patterned Si nano-pillars embedded in...
Article
This study reports a method to reuse GaAs substrates with a batch process for thin film light emitting diode (TF-LED) production. The method is based on an epitaxial lift-off technique. With the developed reclaim process, it is possible to get an epi-ready GaAs surface without additional time-consuming and expensive grinding/polishing processes. Th...
Conference Paper
Full-text available
In this paper we explain detailed how we successfully decapsulated a state of the art FPGA realized in a 45 nm technology and packaged in a BGA housing. For running SCA attacks it is important that the IC is still fully functional after decapsulation. The challenge here is the BGA package since the acid used to remove the plastic can easily destroy...
Article
Full-text available
The integration of dislocation-free Ge nano-islands was realized via selective molecular beam epitaxy on Si nano-tip patterned substrates. The Si-tip wafers feature a rectangular array of nanometer sized Si tips with (001) facet exposed among a SiO2 matrix. These wafers were fabricated by complementary metal-oxide-semiconductor (CMOS) compatible na...
Conference Paper
Full-text available
Some types of physical attacks e.g. optical inspection, fault injections, etc. require the device under attack (DUA) to be decapsulated. But also more common attacks such as analysis of electromag- netic (EM) traces are benefiting from decapsulations since the amplitude of the measured signal is higher and by that allows simpler analysis and better...
Article
Dislocation networks are one of the most principle sources deteriorating the performances of devices based on lattice-mismatched heteroepitaxial systems. We demonstrate here a technique enabling fully coherent Ge islands selectively grown on nano-tip patterned Si (001) substrates. The Si-tip patterned substrate, fabricated by complementary metal-ox...
Article
The integration of germanium (Ge) into silicon-based microelectronics technologies is currently attracting increasing interest and research effort. One way to realize this without threading and misfit dislocations is the so-called nanoheteroepitaxy approach. We demonstrate that a modified Si nanostructure approach with nanopillars or bars separated...
Article
We investigate the structural properties and strain state of Ge nano-structures selectively grown on Si pillars of about 60 nm diameter with different SiGe buffer layers. A matrix of TEOS SiO 2 surrounding the Si nano-pillars causes a tensile strain in the top part at the growth temperature of the buffer that reduces the misfit and supports defect-...
Conference Paper
XRD techniques determined that 270 nm GaP grown on 400 nm Si0.85Ge0.15/Si(001) substrates by MOCVD is single crystalline and pseudomorphic, but carry a 0.07% tensile strain after cooling down to room temperature due to the bigger thermal expansion coefficient of GaP with respect to Si (Fig. 2). TEM and AFM examinations indicated a closed but defect...
Thesis
Full-text available
The complexity of today´s microelectronic circuitry is not only driven by complementary metal oxide semiconductor (CMOS) scaling, but also by integration of high performance modules for various applications (e.g. wireless and broadband communication systems). These mixed signal circuitries are build up by combining digital CMOS technology with anal...
Patent
Full-text available
Heterobipolartransistor, mit einem Substrat aus einem Gruppe-IV-Halbleitermaterial, einem Emittergebiet eines ersten Leitfähigkeitstyps, einer Basisschicht aus einem Gruppe-IV-Halbleitermaterial eines zweiten Leitfähigkeittyps, der dem ersten Leitfähigkeitstyp entgegengesetzt ist, und mit einer Kollektorschicht, die entweder teilweise oder vollstän...
Article
The solid phase epitaxy (SPE) of undoped amorphous Si (a-Si) deposited on SiO2 patterned Si(001) wafers by reduced pressure chemical vapor deposition (RPCVD) using a H2–Si2H6 gas system was investigated. The SPE was performed by applying in-situ postannealing directly after deposition process. By transmission electron microscopy (TEM) and scanning...

Projects

Projects (3)
Project
The aim of the project is to produce the first terahertz quantum cascade lasers using the group IV heterostructures of Si, SiGe and Ge.
Project
The THz part of the electromagnetic spectrum (0.3-10 THz) is currently exploited in commercial security screening systems (weapon detection beneath clothes), medical diagnostics tools (skin and breast cancer, burns, and in ophthalmology) and production-line monitoring (non-destructive test in the pharmaceutical industry). Existing sources of THz radiation are still toolarge and expensive to be a massively deployed in all of the existing and proposed applications, which include large bandwidth wireless communications and the extension of security screening to far-infrared spectroscopic identification of chemicals and explosives up to 10 THz. A lower production cost, a higher level of integration with control electronics, and a broader range of emitted wavelength are all desirable to expand the application of THz radiation. FLASH, will develop a room-temperature THz laser integrated on Si using CMOS technology-compatible processes and materials. The laser, of quantum cascade type, will be assembled using newly developed conduction-band germanium rich heterostructures. It will leverage on the non-polar nature of silicon and germanium crystal lattices to potentially enabling room temperature operation, and will emit over 1 mW of power in the 1-10 THz range. In perspective, the development of the SiGe heterostructure platform will pave the way towards the new field of nonlinear silicon photonics based on band-structure engineering. The consortium includes EU leaders in silicon chip manufacturing, Si/SiGe/Ge epitaxial material growth, laser and band structure modelling, quantum cascade laser design and terahertz/infrared spectroscopy. The proposed device can provide a step-change in compactness, reduced cost, and functionality of source performance, thus enabling large scale use of terahertz radiation in existing fields of application, and open up new fields of application commercially exploited, such as wireless communication and security imaging. FLASH is funded by EC under the FET-OPEN scheme of Horizon2020. Consortium: - Universita Degli Studi Roma Tre, Rome, Italy (Coordinator) - University of Glasgow, UK - IHP GmbH, Frankfurt (Oder), Germany - ETH Zurich, Switzerland - nextnano GmbH, Munich, Germany
Archived project
During decades the complexity of silicon CMOS technology has continuously been increasing, driven by ever rising demands for higher speed and storage capacity. For the most part, these demands could be met by breath taking advances in miniaturization to a degree unthinkable a generation ago. Lately, however, in view of concerns about power consumption, data transmission, and new applications in hitherto inaccessible fields, additional functionalities are becoming more and more urgently needed. New functionalities necessarily imply silicon technology to be extended to other semiconducting materials with optical and electrical properties beyond those of Si alone. In view of its excellent optical and electrical properties GaAs is one of the most important III-V semi-conductors. It is the goal of this project to explore the epitaxial growth by metal organic chemical vapour deposition (MOCVD) of semiconductor stacks based on GaAs on patterned Si and Ge/Si substrates. This will be the first necessary step towards the monolithic integration of elementary optical-device subcomponents, such as waveguides, grating couplers and lasers on a Si CMOS platform. The challenge here is to overcome the problem of crystal defects arising from the large mismatch of lattice parameters and thermal properties which has so far hindered GaAs-on-Si technology to be applied. In our approach the epitaxy will be carried out on specially designed substrate patterns with large aspect ratios and lateral dimensions ranging from several microns to tens of nanometres. This will permit to explore the evolution of dislocation structures and antiphase domains as a function of the pattern size, which defines the transition from an essentially rigid to a compliant substrate regime. The substrate patterning will include sidewall passivation of the etched Si features, permitting the use of selective epitaxy techniques for precise positioning of the compound semiconductor stacks either directly on Si or on selectively grown Ge buffer structures. The relation between pattern geometry and defect structure will be studied by structural, analytical and optical techniques, such as transmission electron microscopy (TEM), atom probe measurements, high-resolution X-ray diffraction (HRXRD) including synchrotron nanodiffraction, micro-Raman and photoluminescence spectroscopy. We intend to design special test structures in order to prove the device quality of epitaxial III-V material on mismatched Si substrates. This will permit to assess lasing action by optical pumping as a preliminary step towards the fabrication of monolithically integrated lasers on CMOS-processed Si-wafers.