Carbon Nano Fiber Probe Cantilever
< Model name / Chip number / Reflex side coated metal >
OMCL-AC160FS-Q / 3 chips / Aluminum
Carbon Nano Fiber Probes (CNF)
The rodlike-shaped CNF probe contributes in data quality retention, even worn after the several dozen times of scanning over the rugged samples of a polysilicon thin film. It achieves consistency in the measurement and eliminates the bothersome frequent chip exchange.
High aspect ratio probe:
The thickness/width of each CNF probe at 200 nm apart from its apex is less than 50 nm. Its aspect ratio is higher than 4. The tip radius of its apex is less than 20 nm, typically 10 nm.
Such fine probe with tip-tilt-compensation enables to access small and deep pits on your sample surface.
Easy-to learn operationality:
CNF are compatible with conventional Olympus standard silicon cantilevers, OMCL-AC160TS. The compatibility brings you a stress-free usability from the very first operation.
A single CNF probe is formed at the apex of probe support or tetrahedral silicon tip.
Below are SEM images of a CNF probe from the front and side, and the last is a magnified view from the front.
|Front||Side||Side (probe apex)||Front (probe apex)|
CNF probe shape : Rod-like CNF with tip tilt compensation at 12 degrees
Probe support : Tetrahedral (tilted)
Probe material : Amorphous carbon (chief material)
As a reference, several images and data taken with the Carbon Nano Fiber probe cantilever are presented below.
Poly-silicon Thin Film
Poly-silicon film deposited by low pressure chemical vapor deposition ( LPCVD ), its surface looks smooth like a mirror macroscopically, however, it looks rough microscopically like a sandpaper. After scanning by 60 images with a conical silicon probe , AFM images had degraded scan by scan due to probe worn (lower right). With a CNF probe, columnar probe, kept their image quality sufficient high (lower left second). It is attributed to the probe profile. CNF probes achieve consistency in the measurement and eliminates the bothersome frequent chip exchange.
Rate of deterioration: Images at first scanning and 60thscanning of poly-silicon with a CNF probe (left) and tetrahedral silicon probe (right)
Silicon, atomically flat surface
Mirror-polishing of silicon wafer surface in atomically flat, is important process for making ideal IC devices. Mono atomic steps looked like sawtooth can be observed on well-processed silicon surface with AFMs. However, image degradation is occurred during scanning even with such flat sample due to the probe worn. With conventional silicon probes, images became foggy in several times scanning. Carbon Nano Fiber probes can overcome that. As in the image below, sawtooth structure is clearly observed even after 85 time scanning.
Mono atomic steps on Silicon <100> surface
Picture, courtesy of Dr.T.Suwa, Tohoku Univ.
Measuring depth of narrow grooves on a sample
CNF probe is a thin columnar probe, then, it can reach bottom of deep grooves of samples. It is worth while trying to use the probe for measuring depth of grooves.
Graph in left shows probe characteristic function obtained by measuring a tip shape characterizer with comb-like structure in cross section, 90 +/- 5 nanometer deep.
In case curves go through the light blue band in the graph, it indicates the probe reach the bottom of the grooves in the width range.
Curve of CNF probe (solid line) came in the band at the grooves of 35 nanometer wide. Dotted line for triangular pyramid probe (OMCL-AC160TS-) as a reference, reached third quarters of the grooves of 50 nm wide, instead.
That is, CNF probes can measure depth of narrower grooves.
Thin aluminum film with the thickness of 100nm is coated on the back side of cantilever for reflecting light from the deflection sensor in the AFM equipment. High reflex for high S/N sensing can be expected.
Dimension of levers and chip (substrates)
|L (µm)||160 (±20)|
|W (µm)||50 (±2)|
|t (µm)||4.6 (±0.8)|
Number of chips in a case : 3 chips (-Q2 series) and 18 chips (-B2 series)
Case : Plastic box with a tacky coating
Chip status : Pre-separated
|Total number of chips|
|Dimensions (LxWxT, µm)||160x50x4.6|
|Resonance frequency (in air, kHz)||300|
|Spring constant (Stiffness, N/m)||42|
|Material||Silicon (4 - 6 Ω・cm)|
|Material reflex coating on the back side||Aluminum|
|Tilt angle||Tip tilt compensation 12 degree (±6 degrees)|
|Width (200nm from apex, nm)||50|
|Tip radius (nm)||10|
|Chip||Shape||Trapezoidal cross section, Round chip-shoulder|
|Dimensions (LxWxT, mm)||3.4x1.6x0.3|
|Packaging||Chip configuration in the box||Pre-separated chip|
|Storage box||Plastic box with a tacky coating|
|Data attached||SEM image (3 chips)|
- Care for Static shock (see an example of tip damage)
The sharper tip needs the more careful handling to prevent static damage to the tip. Use of an anti-electrostatic mat and a wrist band are recommended as when handling laser diode chips. Handling under an ionizer is also recommended.
Please avoid wearing clothes like woolen sweaters, fleece etc when handling the cantilever cases and chips.
- Every good cantilever meets the specifications.
- FAQs on AC (dynamic) mode cantilevers (here)
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