Labview-based automated multichannel curve tracer for field effect transistor characterization.

Date

10-2010

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Nelio C. Altoveros

Abstract

A curve tracer with an automated voltage and current controller was designed, constructed, calibrated and tested. The developed device is able to characterize an 8x8 array of field effect transistors (FETs). LabVIEW® was used in programming the Keithley 2410 C Source Meter, the GW Instek GPD 3303S power supply, the Keithley 6485 picoammeter and the microcontroller devices that are used for the automated data gathering. A graphical user interface was also implemented using LabVIEW®. The GUI allows the operator to enter the drain and gate sweep voltages to be fed to the system, and to select which among the 64 field effect transistors is to be tested. A real-time graph in the GUI shows the IV (current-voltage) characteristic curves for every FET. Two types of FETs namely 2N5457 and 2N5458 N-channel JFETs with different characteristic curves were tested. During FET characterization test runs, the experimental values for common parameters of a FET such as cut off voltage and maximum drain current at shorted gate were determined. Comparing experimental values with the theoretical values obtained from the manufacturer's datasheet, percentage errors of 2.78% and 2.56% were observed for the cut off voltage and maximum drain current, respectively. Demultiplexers were used for the selection of individual FETs to be tested. The effect of these demultiplexers was investigated. It was observed that the difference between having demultiplexers and not having demultiplexers showed correlation factors of 0.9912, 0.9969, 0.9993 for 2N5457 FET and 0.9796, 0.989, 0.9954, 0.9988, 0.9889 for 2N5458 FET at different gate voltages, thus showing that the demultiplexers used resulted to minimal effect on the system's data gathering. Also, by performing 64 trials using the 64 available testing sockets of the FETs, the precision of the voltage and current values were evaluated. The precision test showed standard deviations within a range of 8 x 10E-06 to 6 x 10E-07 for the current readings at same voltages supplied to the system. The run time of the program to generate one family of curves was found to be around 19 minutes for one field effect transistor characterization, as compared to manual data gathering that typically takes around 1 hour. Thus with the implemented automated curve tracer in this study, a faster yet still reliable FET characterization system was developed.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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