The cleanroom of the Institute of Semiconductor and Solid State Physics is divided into four rooms with clean room classes 100, 1000 and 10000. Two rooms with classes 100 and 1000 have yellow room light in order to perform various kinds of photolithographic processes without unintended light exposure. Lithographic processes are realized via blue light exposure in different mask aligners, via holographic laser illumination and with e-beam writing in a scanning electron microscope.
In the 1000 and 10000 cleanrooms two evaporation systems for metallic and insulating layers, a plasma deposition system, two systems for reactive ion etching, an MBE system for Si/Ge and a second for selenide and telluride based IV-VI semiconductors are installed. Additional infrastructure is present to perform all necessary steps from nanoscale semiconductor material processing to exemplary device fabrication.
New cleanroom in LIT Open Innovation Center (OIC)
A new cleanroom facility in the basement of the recently opened LIT Open Innovation Center (OIC) is presently under construction and will be available in the spring of 2020, with three cleanrooms of type ISO 6 (mainly for physics, mechatronics and mathematics) and one cleanroom of type ISO 7 (mainly used by chemistry institutes).
I. Semiconductor Growth
IV-V-VI Molecular Beam Epixaxy (MBE)
for Topological Systems and Multiferroics
The Varian GEN-II MBE system is equipped with effusion cells for PbTe, SnTe, Te, Bi2Te3, Mn, Eu, Sr, CdTe, PbSe, Se, and Tl2Te3 for fabrication of topological insulator and multiferroic thin films and heterostructures on various 2" substrates including BaF2, InP, GaAs, CdTe, KCl, SrF2, Si and Ge in (111) and (100) orientation. In addition, infrared device structures such as VCESLs and self-assembled quantum dots have been grown in this system.
Group IV Molecular Beam Epitaxy
II. Structural Characterization
Atomic Force Microscope (AFM)
Scanning Electron Microscope (SEM)
PANalytical X'Pert PRO Materials Research Diffractometer
The PANalytical X'Pert PRO Materials Research Diffractometer is suitable for coplanar as well as non-coplanar (in-plane) diffraction geometries. Easily applicable optics in modular form (PreFIX) allow for high resolution measurements. Fast reciprocal space mapping can be done with a 1D detector. With in-plane diffraction, it becomes possible to measure diffraction from lattice planes that are perpendicular to the sample surface. The sample holder can hold wafers up to 300 mm diameter.
Optics & Detectors:
- Mirror: W/Si, graded, parabolic, acceptance angle: 0.8°, length: 60 mm.
- Monochromator + Crossed Slits Collimator: 4xGe, asymmetric, flat.
- Hybrid Monochromator + Automatic Absorber: Divergence slit: 0.5°, height: 0.76 mm, dist. to sample: 320 mm. Mirror: W/Si, graded, parabolic, acceptance angle: 0.8°, length: 60 mm. Monochromator: Ge, 2-bounce, asymmetric, flat.
- Triple Axis\Rocking curve attachment: Asymmetric triple axis Ge, 3-bounce, asymmetric, flat.
- Diffracted Beam Mirror: W/Si, graded, parabolic, acceptance angle: 0.8°, length: 60 mm.
- Parallel plate collimator
- Programmable receiving slit
- Xe proportional point detector
- PIXcel 1D detector
A versatile X-ray diffraction instrument with copper rotating anode powered by a 18kW Generator from Bruker AXS (M18XCE) is attached to a custom built 6-circle goniometer from Huber. Several optical elements, which can be combined in various ways allow the setup to be used in medium to high resolution configurations. The whole goniometer is motorized with stepper motors which are controlled by a custom built programmable logic controller rack built by the Forschungszentrum Rossendorf. The measurements are computer controlled by spec, which runs on a Ubuntu Linux PC. The 6-circle Goniometer enables measurements in various diffraction geometries:
- coplanar X-ray diffraction
- non-coplanar X-ray diffraction
- grazing incidence diffraction
- X-ray reflectivity
- grazing incidence small angle X-ray scattering
Optics & Detectors:
- X-ray mirror: Xenocs double bent parabolic multilayer mirror (FOX 2D) for beam collimation
- Monochromators: Two Ge (220) two-bounce channel cut monochromators, which can be used alone or in a Bartels monochromator configuration
- Analyzer (optional): a motorized analyzer stage for use on the detector arm is in development.
- Vantec-1 PSD: Linear detector with ~50µm channel width from Bruker AXS
- Braun PSD: gas flushed linear detector
Both linear detectors have fixed slit systems attached and can also be used as point detectors.
- Huber goniometer head: modified version of the Huber 1003 manual goniometer head with two perpendicular cradles with common center of rotation
- Evacuated sample environment with heater: An evacuated sample environment with heating possibility from room temperature up to 200°C (expandable if necessary). A Kapton window with >180° opening angle in the scattering plane allows the primary and scattered beam to enter the sample environment.
- Motorized piezo stage: For accurate sample positioning an Piezo-driven goniometer head from attocube, with two cradles and two linear translation stages. The sample is mounted in the common center of rotation of the cradles which can be adjusted to the center of rotation of the 6-circle goniometer. The sample can be positioned with µm-precision. (in development)
Seifert XRD 3003
The Seifert 3003 X-ray diffractometer allows for high resolution X-ray diffraction in coplanar geometry with several primary and secondary beam optics configurations. This means high resolution fast reciprocal space mapping with a 1D detector as well as high resolution rocking curve measurements and reciprocal space mapping with an analyzer crystal or secondary multilayer mirror.
Optics & detectors:
- Mirror: graded, parabolic, bent.
- Monochromator: 2 Ge channel cut crystals, symmetric, flat. Usable as just one channel cut, or in Bartels configuration in (220) or (440) setting.
- Multilayer Mirror.
- Channel Cut Analyzer: Ge, symmetric. Can be used in (220) or (440) Bragg condition.
- Slits and Soller Slit
- Meteor 1D linear pixel detector, can be used alone or in point detector mode behind the different secondary optics
Electron Beam Lithography
IV. Material Deposition
Metal Deposition System
Plasma Enhanced Chemical Vapour Deposition (PECVD)
Atomic Layer Deposition System (ALD)
Plasma Assisted Etching
Reactive Ion Etching (RIE)
Femtosecond Pulsed Laser
Center for Nanoscale Semiconductors
This center consists of two optical setups which are being used for microphotoluminescence spectroscopy and quantum optics, as well as devices for the meaurement of thermal conductivity of thin layers.