Flat Band Voltage Shifts and negative charges de-trapping

Excel VBA for select/paste data and create new Worksheet

Due to the large amount of data (~40,000 points in a 40 seconds measurement) obtained from experiment each time. It is essential to develop programs for selecting useful data for further analysis like plotting and calculation.

Excel VBA is used to achieve the requirements. Two programs were written, one is to copy different ranges of data in origin Worksheet and paste them to new Worksheets. The other program copies other ranges of data and paste them to the second columns of newly created Worksheets.

Excel VBA codes are shown below:

Figure 1 copy, create new sheet and paste

Figure 2 copy and paste to existing sheets

Source codes (.bas files) for two modules, click here to download.

2ed Pulsed CV measurement, high-k material, Data

A negative feedback operational amplifier is used in today's pulsed CV measurement. This circuit has more accuracy than previous design.

Pictures below show some settings and waveforms on oscilloscope. Data recorded in the experiment can be found at last. Voltages used are 4V, 4.5V, 5V, 5.5V and 6V. The sample which is a high-k capacitor was broken after the first pulse under 6V.

LabView Setting

Fuction Generator

4 volt

4.5 volts

5 volts

5.5 volts

6 volts, sample broken

Data recorded, please click here.

1st Pulsed CV measurement (Some Analysis)

For pulsed CV measurement,

The whole figure of input voltage is shown below, since the pulsed measurement is very fast, each pulse lasts for about 200us , it is not clear to display results in one graph, so the results will be shown in segmentations.

input voltage plot

For the first segment, the input voltage and output voltage are plotted below:

First segment

In pulsed CV measurement, the output voltage is proportional to capacitance of the sample (the load resistor is relatively small). The above figure generally displays the shape of a CV plot. A detailed calculation for capacitance can be found here:

Some CV plots are shown below:

Segment 1:

segment 1 first down pulse

segment 1 first up pulse

segment 1 second down pulse

Segment 7:

segment 7 up pulse

segment 7 down pulse

Segment 13:

segment 13 up pulse

segment 13 down pulse

Segment 19:

segment 19 up pulse

segment 19 down pulse

1st Pulsed CV measurement (Data)

Continued the experiment left from last time, the oscilloscope is changed and the data can be saved into pan driver. 

The setting file of the measurement is shown below:

Anlg Ch State  Units/Div  Position  Coupling  BW Limit  Invert  Impedance 
 Ch 1:    On     3.13V/     0.0V       DC        Off      Off     1M Ohm  
 Ch 2:    On     13mV/      0.0V       DC        Off      Off     1M Ohm  

Anlg Ch   Probe  
 Ch 1:  1.00 : 1 
 Ch 2:  1.00 : 1 

Trigger  Mode   Coupling  Noise Rej  HF Reject  Holdoff 
  Edge  Normal     DC        Off        Off       60ns  

Trigger Source   Slope   Level 
  Edge   Ch 1   Either  +500mV 

 Time  Zoom  Time Ref  Main s/div   Delay  
Normal  Off   Center    100.0us/   100.0us 

Acquisition Realtime  Vectors  Inf Persist 
  High Res     On        On        Off     

Segmented Current Seg  Actual # Segs  Requested # Segs  Sample Rate 
    On         1             19              19           100MSa/s  

The data from channel 1 which is voltage in is recorded in a  .csv file, please click here.
The data from channel 2 which is voltage out is recorded in a .csv file, please click here.

1st Pulsed CV measurement

It's the first pulsed Capacitance-Voltage measurement on high-k materials. There were some problems. Segmentations of voltage curve were not shown correctly, and data cannot be saved into pan driver.

A pulsed CV measurement of silicon oxide MOS capacitor has been taken. The LabView programming environment is used to control instrumentation which allows rapid measurement of flat band voltage shifts in MOS capacitors incorporating high-k materials.

Pulsed CV measurement uses a programmable voltage source, capacitor and load resistor to form the circuit to plot capacitance voltage curve. The circuit is shown below:

Pulsed CV circuit

The input voltage V_i is a ramp voltage, the component under test (CUT) is shown in the dotted square, the output voltage V_o is measured across a very small load resistor. Calculation principle used in pulsed CV measurement is:

Data Analysis of High-Frequency Current-Voltage Measurement of MOS Capacitor

Full analysis .docx file in Google Drive
Please Click Here 

Some plots used are shown below: