Ultimate nanoprobing at low temperatures
LT NANOPROBE from Scienta Omicron
The low temperature LT NANOPROBE defines a new class of analytical instrumentation that merges scanning electron microscopy (SEM) navigated nanoprobing at LHe temperatures with high performance scanning tunneling microscopy (STM) imaging, spectroscopy and manipulation.
|Four independent scanning tunneling microscopes|
|Excellent STM performance for spectroscopy and manipulation|
|4-Point transport measurements on nanostructures|
|Base temperature T < 5 K|
|High resolution SEM navigation|
A major challenge in the development of novel devices in nano- and molecular electronics is their interconnection with larger scale electrical circuits required to control and characterize their functional properties. Local electrical probing by multiple nanoprobes with ultimate STM precision can significantly improve efficiency in analyzing individual nanoelectronic devices without the need of a full electrical integration.
In order to meet these requirements the LT NANOPROBE has been developed in collaboration with the Peter Grünberg Institut (PGI) (PGI-6, Prof. C. M. Schneider) at the Forschungszentrum Jülich. As a sophisticated instrument it has been specifically designed for local and non-destructive 4-point probe measurements at low temperatures.
Besides STM probe fine navigation and imaging, the excellent STM performance level of the LT NANOPROBE expands applications to spectroscopic mapping and even the creation or modification of nano-structures by an ultimately precise STM probe. The LT NANOPROBE thus opens up new research opportunities in nanoelectronics, spintronics, and molecular electronics.
Microscope stage design
Omicron´s proven scanning probe microscopy (SPM) technology has been taken one step further. Cooling the whole microscope to LHe temperatures requires the stage to be extremely compact with only 100 mm in diameter – a real challenge if 4 STM need to be fully functional, independent and highly stable. An efficient thermal shield compartment allows for temperatures well below 5 K, extremely low thermal drift and thermal equilibrium of sample and probes.
In addition, the integration of high resolution SEM navigation requires a small SEM working distance and thus makes a dedicated STM concept indispensable. A sophisticated shared stack scanner allows for a very compact and flat design, while ensuring highly linear, orthogonal and stable STM scanning characteristics. For ultimate STM performance the microscope stage employs an effective eddy current-damped spring Suspension.
Probe module coarse positioning: XYZ = 5 mm x 5 mm x 3 mm, piezo-electric inertia drives
STM fine positioning / scan range: XYZ ~ 1 µm x 1 µm x 0.3 µm @ LHe
STM resolution: Atomic resolution, Z-stability better 10 pm @ LHe
STM pre-amplification: 3 nA / 330 nA ranges lowest STM imaging current < 5 pA Omicron SPM PRE 4E
STM pre-amplifiers switch: Signal re-routing from STM pre-amplifier to external BNC connector, remote or TTL control Omicron CSW4 switch
SEM resolution: 30 nm @ LHe 17 mm working distance, in lens SED
SEM XY positioning: XY = 4 mm x 4 mm, Z = 3 mm External XY manipulator
Probe / tip exchange: In-vacuum spring loaded tip carrier (non-magnetic) exchange by wobble-stick
Sample and tip storage: 28 storage positions inside analysis chamber
Sample and tip transfer: Fast entry lock with 5 transfer positions
Sample stage coarse positioning: XY = 4 mm x 4 mm, piezo-electric inertia drives
Sample exchange: In-vacuum wobble-stick transfer
Sample size: 10 mm x 10 mm (Omicron standard sample flat plates)
4 mm x 4 mm addressable by sample stage motor
Sample temperature measurement: Si diode sensor at sample stage