Software Development based on LabVIEW for DC

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4.3.6 <strong>Software</strong> development of a LABView programme for the DC and
RF characterisation of Heterojunction Bipolar Transistors
Student: Ingo Nannen
Scientist: Jörn Driesen, Silja Ehrich
Introduction
The rising complexity of Integrated Circuits demands an accurate DC and RF characterisation. The
development and advancement of reliable and multifunctional software is therefore of high
importance.
Two different porgramms have been used by the research team of HLT as a standard in the past.
The instant use of BASIC software for the DC measurements and Agilent Vee for RFparametrisation
was rather uncomfortable. One of the disadvantages of this system was the
incompatibility of both software data types.
Based on the main features of both characterisation programms, the new LABView <strong>Software</strong> has
been developed in order to determine both DC and RF parameters of the DUT simultaneously.
Direct current and DC-Voltage supply is provided by SMU HP4142B. RF analysis is established by
Analyzer HP8510C. Both devices interact via the GPIB-buss with the computer. The adjustment
setting and control of the parameters is managed by diverse servo loops and subroutines
implemented in the labview software.
The following DC characteristic curves can be determined by the implemented measurement
software.
output characteristics
transfer characteristic
input characteristic
diode characteristic
gummel-plots (forward and reverse)
Figure 1 shows the control panel for the DC analysis. The measured data is displayed by indicator
3. Were it is important the programme switches automatically between cartesian and logarithmic
coordinates if necessary. The active values for the different voltages and currents during the
measurement are displayed by indicator 5. Indicator 4 shows the progress of the measurement.
The input lead resistance can be determined in order to improve the accuracy of the measurement.
The voltage drop on the lead is considered by the calibration of the DC power supply by the
software.
The user should change the Mainpanel for RF – measurement to do a RF characterization of a
transistor. The Mainpanel is shown in figure 2. The programme includes different ways to adjust an
operating point as shown in indicator 12. The possibilities adjustments are:

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base current and collector – emitter voltage
base –emitter voltage and the collector – emitter voltage
collector current and collector – emitter voltage
collector current and base – collector voltage
base current and base – collector voltage
Servo loops were created for the four last mentioned adjustments.
The programme is able to present the results of the measurement within a Smith – Chart, amplitude
– frequency – chart and phase – frequency – chart.
Data can be stored in different file formats. Citifile format and HLT format used by the BASIC –
programm for DC measurement are available as well as Touchstone format for data acquired by
RF – measurement.
References:
[1] Handbook HP 8510C Vector Analyzer
[2] Handbook HP 4142B Parameter Analyzer
[3] F.J. Tegude
„Technische Elektronik 1,2“
Script of the lecture, 2003
[4] F.J. Tegude
„Technische Elektronik 1,2“
script of the lab, 2003
[5] „LabVIEW7 Express“
National Instruments, 2003
[6] HP VEE Advanced Programming Techniques
Hewlett Packard, 1997

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Figure 1. Mainpanel for DC – measurement

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Figure 2. Mainpanel for HF – measurement