Emerging technologies drive test advances

Linda Rae of Keithley Instruments explains that new power requirements present challenges for test engineers.

Larry Maloney, Contributing Editor -- Test & Measurement World, 12/16/2011 12:29:49 PM

Linda C. Rae President Keithley Instruments Cleveland, OH Linda Rae was named president of Keithley Instruments, a Danaher company, in 2010. She joined Keithley in 1995 in product marketing and then served as head of the Component Test Group as well as the company’s Optoelectronics Group. She was later promoted to senior VP and GM. In 2005, she was named executive VP and COO. Rae earned a BSEE degree from the University of Florida and an MSEE and MBA from Case Western Reserve University. Contributing editor Larry Maloney conducted a phone interview with Linda Rae on products that Keithley has developed to meet the test and measurement needs of emerging technologies. A version of this article appeared in the Dec. 2011/Jan. 2012 issue of Test & Measurement World. To read past “Viewpoint” columns, go to www.tmworld.com/viewpoint

Q: How are the changing needs of test engineers affecting the kinds of products that Keithley is introducing?
A: One of the big changes we see is the need for wider dynamic range. This is driven by the growing interest in new power and energy efficiency in devices and materials. We see this trend at the semiconductor level and at the device and module level. As power requirements increase, the dynamic range of measurements that customers have to make is getting wider.

Engineers have to make measurements not only of high voltage and current but also low current and low voltages. If engineers want to use one equipment setup, it’s becoming more challenging to get good leakage-current measurements or break-down voltage measurements while also biasing at a very high power level or a very high current or voltage level. These requirements for dynamic range are influencing a lot of the products we are developing, and these new instruments must still deliver a high level of sensitivity, accuracy, and speed.

Q: What applications led the way in Keithley’s business recovery in 2010 and 2011?
A: Certainly, we saw a lot of recovery in the semiconductor side, where there has been significant capital spending both for R&D and production test. Across many industries, we saw renewed spending on test for device characterization and production testing, as well as for general R&D. Our focus continues to be on the semiconductor industry and on the device side, where we sell a lot of our SMUs (source-measurement units) and semiconductor test systems. The underlying technology behind the applications we serve is continuing to evolve, and that creates more opportunities for future growth.

Q: What emerging technologies present some of the biggest challenges to test engineers?
A: In the semiconductor industry, there’s the push to develop new materials that will help ensure the continued application of Moore’s law, as researchers seek faster switching and operating speeds. Wider power requirements affect not only dynamic range, but also the way engineers make measurements. For example, we’re focusing more on pulse test techniques that allow you to tightly limit the amount of time that you expose a material to energy in order to minimize self-heating effects that can influence measurements and damage a device. This is especially important in nanoscale devices. Other emerging technologies that present new challenges for test instruments include new types of nonvolatile memory, printable materials for electronic displays, and alternative lighting, such as high-brightness LEDs.

Q: How does Keithley benefit from its close relationship with the R&D community?
A: That relationship goes back 65 years, and it remains a key source of knowledge on technological changes and trends that will impact future measurement applications both at the R&D level and in production. In 2010, Drs. Andre Geim and Konstantin Novoselov won the Nobel Prize in Physics for their work on graphene, a single-atom-thick form of carbon with many potential applications in electronics, aerospace, and automotive. These scientists employed several Keithley instruments, including our Model 2400 SourceMeter and the Model 2182A Nanovoltmeter. This was the third instance of Keithley’s involvement with Nobel Prize winners. Beyond Nobel laureates, if you look at the number of patents and scientific papers that specifically mention our SMUs, you’ll find about 5000 references.

Q: Are you seeing significant growth in test and measurement applications for alternative energy, such as solar energy and fuel cells for electric cars?
A: Yes. It's a very big area for us. We are doing a lot of work with solar cells and have a Web-based seminar on the topic. As noted, we also are doing quite a bit of work with high-brightness LED manufacturers. Our recently introduced 2651 SMU specifically targets energy-efficiency applications, such as fuel cells and LEDs.

Q: This year, Keithley's Model 4225-PMU Ultra Fast I-V Module won an R&D 100 award. What's so special about this product and what are its key applications?
A: I talked earlier about new developments in semiconductors, such as materials and nonvolatile memory. As chip geometry shrinks and material structures change, the sensitivity of devices to self-heating becomes higher. So, the challenge in test when you are making current, voltage, or resistance measurements is this: How do you get enough energy through the device to get a good measurement but still keep the time duration short enough so that you don't change the fundamental behavior of the device? And that is exactly the function of the Model 4225-PMU Ultra Fast I-V Module. It provides engineers with ultra-fast waveform generation and current/voltage measurement in a single instrument. It is all integrated in two channels on a card that fits into our 4200 semiconductor characterization chassis. The end result is a complete characterization system for doing your DC, CV, and ultra-fast pulsed I-V in one package and one user interface.

Q: Can you touch briefly on other significant product introductions of the past year?
A: Two in particular tell a very nice story about what we believe is Keithley's leading position in SMUs, which we've been producing since the 1980s. Our line now consists of SMUs in benchtop and rack formats, as well as SMUs in integrated systems, such as the Model 4200 semiconductor characterization system. The two new products I would like to mention demonstrate the wide range of capabilities of our line. The 2651A is the highest-power and highest-current SMU on the market: 50 A and 40 V for 2000 W of power. That 50-A capability addresses a lot of those energy-efficiency and high-power applications that we talked about earlier. These devices have to be measured at higher and higher bias currents to mimic the operating environment in which they'll be used. At the same time, manufacturers still must characterize leakage currents and conduct low-resistance measurements, and it's this wide dynamic range that the 2651A gives you.

Another very significant product that we've just introduced is the Model 2401 SMU. We believe it is the lowest-cost precision SMU on the market today for its level of performance. Even though many of our customers are pushing the envelope with high power, energy efficiency, and new materials and need to make fast, sensitive measurements, they may not always need a full-blown 200-W instrument. The Model 2401, a 20-V, 1-A, 20-W product, can answer many application needs. A very flexible instrument, it can source and measure voltage, as well as measure current. It also replaces a programmable power supply used with a DMM (digital multimeter). So, Keithley is introducing products at the low-end of the cost spectrum, often for R&D applications, as well as very high-end products, such as the 2561A, for R&D and production.

Q: Besides solar-cell technology, what are some of the other topics that Keithley is targeting in Web-based seminars?
A: A lot of them fall into one of two categories. One category focuses on new devices and new materials, such as solar cells, high-brightness LEDs, nonvolatile memory, organic electronics, and graphene material. These seminars discuss how to make good measurements in these applications. The other category of seminars deals with innovative measurement techniques, such as Hall-effect measurements, low-voltage, low-resistance measurements, or bias temperature instability assessment, which is a hot topic in the semiconductor field.

Q: Looking ahead, what applications will lead the way for Keithley over the next five years, and what global markets offer the most opportunity?
A: From an application standpoint, we'll continue to focus on many of the same areas we've already discussed, such as semiconductors, device and materials characterization, and alternative energy. As for global markets, all of them are important to us. Certainly, emerging markets get lots of press and attention, since they are growing the fastest, but the developed markets, such as the US, Europe, and Japan, continue to be very important sources of R&D, as well as emerging technological trends. T&MW