Specifications

3.2.2 User-fabricated test fixtures

If the DUT is not applicable to Agilent-supplied test fixtures, create an application-specific test

fixture. Key points to consider when fabricating a test fixture are:

(1) Residuals must be minimized. To minimize the residuals, the 4TP configuration should be main-

tained as close as possible to the DUT. Also, proper guarding techniques will eliminate the

effects of stray capacitance. For details, refer to “Practical guarding techniques” in Section 3.4.

(2) Contact resistance must be minimized. Contact resistance will cause additional error. In the case of

the 2T configuration, it directly affects the measurement result. The contact electrodes should

hold the DUT firmly and should always be clean. Use a corrosion-free material for the elec-

trodes.

(3) Contacts must be able to be opened and shorted. Open/short compensation can easily reduce the

effects of the test fixture's residuals. To perform an open measurement, the contact electrodes

should be located the same distance apart as when the DUT is connected. For the short mea-

surement, a lossless (low impedance) conductor should be connected between the electrodes, or

the contact electrodes should be directly interconnected. If the 4T configuration is kept to the

electrodes, make the connections of current and potential terminals, and then make an open or

short as shown in Figure 3-9.

Figure 3-9. User-fabricated test fixture open/short methods

DUT electrodes

DU T

Contact

electrodes

(a) DUT connection

(b) OPEN measurement

Low loss

conductor

Low loss

conductors

3-8