ProbeStation

CERN HGTD Probe Station

Introduction

This twiki contains instructions for using the HGTD probe station to make IV or CV measurements.

Location: 161/1-006

Equipment

Experimental setup

  • A Keithley 2410 source meter (on loan from the CERN ITk Group, who have our thanks!)
  • A Keithley 6487 picoammeter (on loan from the CERN Epool)
  • A micro PC (Windows 10/Linux)
  • A probe station (on loan from the CERN ITk Group)
  • A vacuum pump (to ensure that the sensor remains in place on the chuck)
  • XIMEA camera to take pictures of the sensor through the microscope
  • You can install the camera software here (already installed on lab PC): https://www.ximea.com/support/wiki/allprod/XIMEA_CamTool
  • To open the software click the xiCamTool shortcut on the desktop (applies in both Windows and Linux)
  • Make sure the light is on (and the source meter is off!) in the probe station or no image will be visible!

ProbeStationLabels.001.jpeg

Pin controls

  • Pins are used to supply the HV, ground the guard ring and connect the sensor pad, as shown in the left image below.
  • The pins are connected as follows (as illustrated in the lower right schematic):
    • the pin closest to the cabinet door is to ground the guard ring,
    • the middle pin provides the HV to the chuck,
    • the further pin is to measure the current through the sensor pad.

20190605_131434.jpgPinConnections.001.jpeg

  • To position the pins on the pad or guard ring is tricky. Look through the microscope and use the small knobs on the needle mounts.
    • The function of each of these knobs is shown in the schematic below: PinDiagram.001.jpeg

Instructions for measurements

The HGTDSensors twiki contains instructions/recommendations for making sensor tests. Currently we're keeping the CERN team measurements in this spreadsheet.

To set up the PC for IV or CV measurements:

  • Switch on computer, booting up Windows
  • Load up labview project:
    • Documents → Labview project → cviv-daq → CVIV
    • Select CV-IV-control.vi from the list of options displayed in LLB Manager
    • When the CV-IV-control.vi project opens, click on the Arrow right, MOVED TO... button on the menu bar
      • This takes you from edit mode to running mode
  • Fill out the relevant fields in the labview GUI according to the measurements you wish to make (see following sections).

IV (floating guard ring)

Labview settings

Parameter Setting Comment
Device name Sensor name Usually this should be the name written on the sensor packaging. This will be the name of the folder in which the results will be stored.
Drop down menu to right of "Device name" pFZ Default assuming non-irradiated sensors.
Tester  
Type of measurement IV Select from drop-down menu.
Start 0 V  
Stop -100 V This is the max voltage for the scan (will differ between sensors). Note that the value must be negative.
Number of steps Calculate (2V) e.g. Start: 0, Stop: -100, Number of steps: 50
Step mode linear  
Compl. Stop ON This ensures that the measurement cycle will cease, and the voltage ramp down, should the sensor reach the compliance you set.
GPIB 21 Port for Keithley 2410
Integration time 3 [20 ms]
Averaging (count) 3 Number of measurements taken at a single voltage point for averaging.
Compliance. 1e-6 A Sensor dependent (have seen nA currents for HPK Type 1)

IV (grounded guard ring)

Connecting the sensor

  • Ensuring the voltage source is off, open the probe station cabinet and switch on the light.
    • The light switch is located in the back left-hand corner of the cabinet.
  • Turn on the vacuum pump.
    • Turbulence from the pump the instant it is switched on will cause the sensor to move violently if you try to turn on the pump after placing the sensor!
  • Using plastic tweezers, gently place the sensor onto the chuck, positioning it over the small hole in the centre.
    • The sensor should completely cover the hole so that the vacuum is effective.
  • Position the needles on the sensor, as shown below.

PinsOnSensor.png

  • Switch off the light and close the cabinet doors.

Labview settings

Parameter Setting Comment
Device name Sensor name Usually this should be the name written on the sensor packaging. This will be the name of the folder in which the results will be stored.
Drop down menu to right of "Device name" pFZ Default assuming non-irradiated sensors.
Tester  
Type of measurement IV with two I-meter Select from drop-down menu.
Start 0 V  
Stop -100 V This is the max voltage for the scan (will differ between sensors). Note that the value must be negative.
Number of steps Calculate (2V) e.g. Start: 0, Stop: -100, Number of steps: 50
Step mode linear  
Compl. Stop ON This ensures that the measurement cycle will cease, and the voltage ramp down, should the sensor reach the compliance you set.
V source and I meter Keithley 2410 Select from drop-down menu.
I meter Keithley 6487 Select from drop-down menu.
GPIB address (Keithley 24xx) 21 Port for Keithley 2410
GPIB address (Keithley 6487) ?? Port for Keithley 6487
Integration time 3 [20 ms]
Averaging (count) 3 Number of measurements taken at a single voltage point for averaging.
Compliance. 1e-6 A Sensor dependent (have seen nA currents for HPK Type 1)

Analysis of IV/CV data:

Useful links

-- EmmaKuwertz - 2019-05-21

Topic attachments
I Attachment History Action Size Date Who Comment
JPEGjpg 20190605_131434.jpg r1 manage 3861.1 K 2019-07-10 - 19:40 EmmaKuwertz Pins on chuck
JPEGjpeg PinConnections.001.jpeg r2 r1 manage 124.5 K 2019-07-10 - 20:09 EmmaKuwertz Diagram showing which pin connectors go where
JPEGjpeg PinDiagram.001.jpeg r1 manage 124.5 K 2019-07-10 - 20:00 EmmaKuwertz Pin controls
PNGpng PinsOnSensor.png r1 manage 1153.3 K 2019-07-10 - 20:49 EmmaKuwertz  
JPEGjpg ProbeStation.jpg r2 r1 manage 4807.1 K 2019-07-10 - 20:29 EmmaKuwertz  
JPEGjpeg ProbeStationLabels.001.jpeg r1 manage 440.4 K 2019-07-10 - 20:37 EmmaKuwertz  
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Topic revision: r2 - 2019-07-10 - EmmaKuwertz
 
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