ENSC 495/851 Lab Electrical and Device Measurements V1.0 Mar. 25 2015 Glenn Chapman

Testing the devices is done after level 4 has been completed and wafers ENSC 495 students will do at least parts 1 to 5 on one chip. Graduates with a minor project the full set of tests on many positions. For the curve tracer use a digital camera to take the curve traces for the characteristics. Download the Tektronix 576 manuals to consult on using the curve tracer. Basic Chip Layout The ENSC 495/851 test chip layout (Figure 1) is a 5mm x 6mm (W x H). There will be more than 200 copies of this test chip on each wafer. The smallest feature size of these devices is 20 microns. Most lines are 40 microns wide. Figure 2 shows the labelled structures for the chip. Start with chips near the wafer centre.

Figure 1: 5x6 mm ENSC 495/851 chip

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Figure 2: Micromanipulator probe

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Figure 10: Solar cell diode Figure 11: Solar cell with light on. (5) NPN Transistor Test Test the dual-base-contact NPN transistor using the curve tracer. Use the substrate transistor contact as the collector (See Figure 12 for the Collector, Base and Emitter contacts). Measure the transistor characteristics (in the dark). Measure the Base Collector, Base Emitter and Collector Emitter IV characteristics (Fig 13-15). Watch for breakdown of CE curve (it may be bidirectional diode). The put curve tracer in NPN transistor mode and take full characteristics (Fig. 16) What do the transistor action characteristic curves look like (note the base current, collector current etc)? Calculate the transistor beta (current gain) at collector currents around 100µA and 3mA.

Figure 12: NPN Bipolar, N Mosfet and P Mosfet pads

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ansistor charracteristics