Silicon Cantilever for Electrical Measurement Classic
for Electric measurements
|Small quantily unit||Wafer unit|
|18 chips/unit||375 chips/wafer|
|Small spring constant (k) type Silicon probe
with platinum coating
OLYMPUS OMCL-AC240TM- series cantilevers; platinum-deposited cantilevers are suitable for conducting scanning probe microscopy (SPM) in air such as electric force microscopy (EFM), Kelvin probe force microscopy (KFM). Unprecedented sharpness of 15nm (typ.) radius as a metal coated probe is worth trying in researching devices.
Platinum-deposited Tetrahedral tip cantilever
Outstanding features of Tetra tip cantilever
1) High electrical conductivity:
The platinum-deposited probe shows lower conductivity in one and a half orders of magnitude than that of highly doped silicon probes. Its probe resistance of 350 ohms is sufficiently low for electric measurements required high electro-potential resolution. The surfaces of precious metal coatings are free from oxidization and are electrically stable.
2) High resolution:
The apex of 15 nm (typ.) radius is prominently sharp among metal-coated probes (see the tip apex). The thin and sharp tetrahedral probe reveals sample surface precisely both in electrically and in topographically.
3) Easy to access where you want to see:
OMCL-AC240TM- Series has a tetrahedral tip on the exact end of the cantilever. Since the tip isn't hidden by the body of cantilever, it can be positioned exactly at a point of interest using an optical microscopy. - Tip View feature - Click here for an example (image size 40k)!
Check Scan line profile
Below are a schematic sectional view and SEM images of a platinum-deposited silicon tetrahedral tip.
- Tip shape : sharpened tetrahedral (tilted)
It shows good symmetry viewed from the front and is inclined viewed from the side.
Considering this geometric feature, choose the fast scan (X) direction.
- Tip height : 15 µm (9 to 19 µm)
- Tip radius : smaller than 25 nm (15 nm (typ.))
- Tip angle : less than 35 degrees ( *)
- Tip-side coating material : platinum with thickness of 20nm on the lever portion
- Basic tip material : single crystal silicon (semiconductor, N type, 4 - 6 ohm.cm)
Dimensions of levers and chip (substrates)
Cantilever and chip of OMCL-AC240TM series
Lever thickness of OMCL-AC240TM- is typically 2.8µm.
Cut off shoulders lessens contact between the chip and the specimen when the tip has engaged to the sample (illustration right above).
- Coating material : Platinum
- Thickness of platinum : 20 nm (at the lever portion)
- Probe resistance : Approx. 350 ohms
Probe resistance is studied with the setup illustrated in right.
- Position to electrical contact
In attaching the probe chip to your SPM instrument, ellectrically connect to the chip in the cantilever side for stable measurements (see illust. right). It is not expected that the aluminum layer (reflex coating) shows enough conductivity because the surface of the aluminum layer is covered with oxide layer.
- Material : Aluminum
- Thickness of aluminum : 100 nm
Mechanical properties of levers
Stiffness [N/m] and resonant frequency [Hz] of each cantilever are Calculated values<.
(0.5 - 4.4)
(45 - 95)
(9 - 19)
Mechanical Q factors of OMCL-AC240TM- from 100 to 200 in air, are measured in our experiments. However, the final properties deeply depend on the holding condition of the chips in your AFM.
In vacuum, the Q factor increases up to 10 times.
Small quantity unit : OMCL-AC240TM-B2
- Number of chips in a case : 18 chips
- Case : Gel-Pak container
- Chip status : Pre-separated Chips are separated from each other and are placed in the Gel-Pak.
Inspections are carried out when the chips are in the wafer stage; those which pass the strict quality test are placed on the gel sheet ready for supply.
Wafer type unit : OMCL-AC240TM-W2
- Number of chips in a wafer : 375 chips
- Case : 4 inch wafer case (not Gel-Pak)
- Chip status : supported to frame with support arms
Chip separation from the wafer is easy due to the frame structure (Illust. above).
Wafer pattern of OMCL-AC240TM-W2 ( 4 inch. wafer ) is shown in the above photo.
Tip inspections are performed by sampling 10 tips at random from the wafer. (Blank area in the wafer)
- Microscopic / nanoscopic measurements of electric characteristics of semiconductor devices
such as electric force microscopy (EFM), Kelvin probe force microscopy (KFM) operating in AC mode.
With care for tip worn, OMCL-AC240TM- is also available for scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) in contact mode.
- Scanning probe lithography
- Nanometer-tool applications for nano-technology and nano-biology research
Electric knife, stick, scraper. Small electrode.
- Care for Tip wear (see an example of worn tip)
Wear of the platinum coating is to occur in contact mode techniques so that operators are required to pay attention to the shape of the probe apex. While in imaging, change of image quality reflects the degradation of the apex.
- 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.
- We guarantee more than 90% good cantilevers in this product series. Every good cantilever meets the specifications.
- FAQs on conducting cantilevers(here)
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