RTAC104 AFM References in Package

Transcription

1 Radiant Technologies, Inc. 2835D Pan American Freeway NE Albuquerque, NM Tel: Fax: RTAC104 AFM References in Package Date: December 16, 2014 Summary: The Type AC package contains two identical PNZT capacitors with platinum electrodes each having an area of 100, Cap A is a standard AC104 capacitor clamped to the substrate. Its surface will move ~16Å at ±20 volts. Cap B has had the substrate etched out from underneath the capacitor so it is free to move with voltage application. It can move as much as 2.5µm at ±20 volts. Each die is packaged on a four-lead TO-18 header without a lid so the capacitors are visible. One package lead connects to the case and is labeled GND. The two capacitors share a single COMMON but have separate leads for their other electrodes. The COMMON lead connects to their bottom electrodes. The headers are supplied with plastic sleeves to protect the bond wires. The sleeves must be removed prior to probing with an AFM and replaced after use. Top view TO-18 Header COMMON CAP A CAP B CASE Cap A Common Cap B Temperature Range: -0 C to 85 C. Do not exceed 85 C. Maximum Test Voltages: 20V for the membrane. 30V for the standard capacitor Structural Specification: AC 1µm-thick 4% niobium-doped 20/80 PNZT Capacitor Size: Total PZT Lead Content per Die: RTAC ,000µ 2 BLUE 1.7 micrograms Recovery: The platinum electroded capacitors are prone to fatigue and imprint. They are tested at their saturation voltage at shipping and may be imprinted when received. PNZT imprints slowly at room temperature. There is a recovery procedure that will fully recover the capacitor from imprint. The recovery procedure will not repair fatigue loss. The recovery procedure may be executed multiple times on a capacitor. To recover a Type AC standard capacitor (Cap A), execute a 25V square wave at 1Hz for 100 seconds at any temperature. The Cap B membrane may be recovered using a 20 volt 1Hz sine wave for 10 to 100 seconds. Fatigue cannot be recovered. The capacitors will lose ~50% in 1x10 6 cycles. EDU Compatibility: The BLUE capacitor is too large to be measured by the EDU.

2 Reference Die Geometry: Cap B TE B Capacitors COMM BE Cantilever 100,000 2 Capacitors A Capacitors Bottom Electrode The capacitors in the AFM reference are covered with a glass passivation layer. Electrical contact directly to the top surface of the top electrodes is not possible with a conductive AFM cantilever tip. The capacitors must be connected to the tester using wiring. Warnings: Radiant tests these capacitors prior to shipping. The imprint clock starts when Radiant first runs a full hysteresis loop in each capacitor. The user should 1) store the capacitors in the dark to protect them from exposure from fluorescent light since the packages do not have lids and 2) Periodically run recovery procedure on the each capacitor. Imprint accelerates with increased temperature so the capacitors should be stored at or below room temperature. The membrane capacitor is strong for its thickness but is fragile in the real world. Cap A TE 1. Do not attempt to touch the membrane with anything other than a mechanically controlled probe tip or displacement sensor. 2. Do not exceed 20 volts on the membrane and do not use a square waves or pulses. It is possible to break the membrane with excess voltage and/or steep voltage ramps. 3. The polarization hysteresis loops for the membrane and the solid capacitor will appear to be different. This is most likely due to the large difference in residual stresses of the two capacitors. Radiant Technologies, Inc. 2

3 P o l a r i z a t i o n ( µ C / c m 2 ) & D i s p l a c e m e n t Application: The capacitors are intended to be used to verify the capture of large signal displacement butterfly loops by Atomic Force Microscopes. The solid capacitor clamped to the substrate will move approximately 16Å at ±20 volts at 1 khz. Three Sequential B utterflies - 60 second D elays [ Solid reference ] Adv P 3: Polarization (µc/cm2) Adv P 2: Polarization (µc/cm2) Adv P 1: Polarization (µc/cm2) 30 Adv P 3: Polarization (µc/cm2) Adv P 2: Polarization (µc/cm2) Adv P 1: Polarization (µc/cm2) V o lta ge Radiant Technologies, Inc. 3

4 The membrane will move approximately 2µm at ±20 volts at 0.1 Hz. The TO-18-mounted devices are inserted into the AFM on an AFM Reference Board. Length 3.0 (76.2 mm) Length without tabs 1.4 (35.7 mm) Width 1.0 (25.3 mm) Thickness 0.94 (2.4 mm) NOTE: The tabs can be removed to shorten the length of the PCB. The PCB can be filed down to a smaller footprint as long as the solder holes, the socket pin holes, and the traces between them are not cut. A Dremel tool is recommended. Radiant Technologies, Inc. 4

5 Sometimes, if the header is pushed all the way to the surface of the board, the pin sockets may contact the header and short the isolated pins of the header. If this occurs, pull the TO-18 header slightly away from the board surface. The outside tabs of the board may be broken off to fit in a microscope or AFM. Solder points are provided to connect to the four pins of the TO-18 package to allow electrical stimulation of the two capacitors during AFM scanning without having to use a conductive cantilever tip. For mounting the AFM Reference Board on the Radiant PNDS Ångstrom-level displacement sensor, add a plastic chuck to the bottom of the board. Connecting wires to the PCB are shown in the image below. Radiant Technologies, Inc. 5

6 Also available is a blank sample board for mounting custom samples fabricated by customers. Solder wires to the pin holes on the PCB to connect a tester to the sample. On the board below, the silicon substrate containing the sample has been glued to the generic blank board. Its bottom electrode has been connected to a PCB pad by soldering a wire to the pad and to an exposed patch of bottom electrode. The pad has a trace to a solder pin hole through the PCB to allow the bottom electrode to connected by wire to the tester. With this sample configuration, the top electrode of the capacitor must be contacted during testing by using a conductive AFM cantilever connected to the tester stimulus output port. The blank board has four solder pads and four associated solder holes. Contact Radiant Technologies for assembly instructions. Radiant Technologies, Inc. 6