“My PhDs weren’t allowed to leave without leaving something on the table”

A pioneer in the design of microelectromechanical systems (MEMS) with an additional passion for everything mechanical, a pragmatist and a very good teacher. That’s professor Bob Puers in a nutshell. He was chosen lecturer of the year in 2018 for his excellent MEMS training.

A curious course with overwhelming feedback from the trainees – that’s how Bob Puers describes the MEMS training course he taught in 2018 to a group of fifteen industrials from Pakistan. Puers: “It was held in China because of difficulties with the exchange of Pakistani. The trainees were all extremely willing to learn. I really appreciated this eagerness and also the particularly good interaction with the group. We had a lot of discussion on a very high level.”

In their feedback, the trainees said about Puers: “It was an excellent training both in terms of contents and presentation. The trainer was exceptional in answering questions raised” and “The professor’s way of teaching is extraordinarily good.” This positive feedback resulted in a review score of 9.8 out of 10 and the title “Lecturer of the year 2018.” Puers is modest about his contribution and points out that all the praise is probably due to accidental circumstances. However, when explaining his way of teaching and his knowledge about microelectromechanical systems (MEMS), it’s easily understood how he earned the title.

Bob Puers has always stimulated his PhDs to physically build a device. 

The scientist

Puers’ MEMS experience goes back to his study in electrical engineering. He was very interested in research and had a special passion for everything mechanical. When he came in contact with Raoul Vereecken, a urologist at the University Hospital in Leuven, he got involved in the development of portable, implantable medical electronics. He continued his career in this domain and started his own research group at the KU Leuven in 1988. Soon he had the disposal of his own cleanroom to fabricate devices such as pressure sensors, accelerometers and flow sensors.

In his research, Puers focused on the application of medical implantable electronics and the development of technology to produce sensors – he’s always been motivated to develop devices and is working in a pragmatic way to realize this. If Puers knows a certain principle works, he doesn’t delve too much into the details of the theory but uses this knowledge to put it into practice and make new devices. And being a man of practice: he’s always stimulated his PhDs to physically build a device. As Puers puts it: “My PhDs weren’t allowed to leave without leaving something on the table.”

Puers continues: “In our cleanroom, I developed lithography and application techniques with our group of researchers. We made more sophisticated mechanical structures – on a miniature scale. The whole process of developing a very small mechanical structure, integrating it in an electronic component – to convert the mechanical signal into an electronic one – and finally building a sensor out of it – that still fascinates me.”

There have been many developments in Puers’ discipline. “Back in 1985, our group was one of the first to develop accelerometers. These devices were ground breaking at the time. Nowadays, accelerometers are integrated into commercial products like smartphones and cars at incredibly low cost. There are quite a lot of devices we laid the basis for, ideas that were taken over by the industry later on. So, we had to search for new research domains several times.”

MEMS developments are still ongoing. The current trends are far-reaching miniaturization and very low power consumption. This makes sense, for many sensors are applied in portable medical applications and thus have to be as energy efficient as possible.

The teacher

As a KU Leuven employee, teaching was part of Puers’ tasks.

He started as a teacher of courses in biomedical electronic systems. Later on, he also taught about MEMS production technology. These courses still form the basis of his MEMS systems training at High Tech Institute.

“It’s challenging to educate people and to get them excited about the science domains that you find fascinating yourself,” Puers explains. “You’ll never get them all interested. Only about one third to half of the university students get excited about the subject, the others only do what they’re told. However, High Tech Institute trainees are always people with specific interests who share my enthusiasm. They usually have some experience already, so we have a lot of detailed and specific discussions during the courses. I really like that interaction.

Puers started his MEMS training course for High Tech Institute in 2009 – being a specialist, he was asked to educate people about MEMS. His goal is to introduce his trainees to the domain. “I want them to know more about all the techniques that have been developed over the years to produce micromechanical systems. I explain the possibilities and the impossibilities of MEMS, zooming in at system level. About half of the MEMS training I spend on the instruments we have at our disposal to build a sensor or actuator. These are all necessary techniques, like etching, bonding, packaging and coating. In the second part of the training, I teach the trainees about all kinds of successful applications, like flow and pressure sensors, optical systems and medical implants. In the end, the trainees should know what’s possible and what’s almost impossible. I want them to be able to judge how realistic new concepts are.”

His vast MEMS experience, being involved from the very beginning, makes Puers a knowledgable teacher. But he’s also skillful in tuning to his audience. “I always answer questions that pop up during the course. Sometimes I can do that straight away because I know the answer from experience. If I don’t know the answer, I get back to the issue the next course day. I like to anticipate questions and feedback in my training. Teaching is a process of evolution. In every new course, I use the experience of previous courses, so my intellectual baggage as a teacher is continuously being enriched. In this way, I’m constantly refining my courses and adjusting them to my audience and their prior knowledge.”

This article is written by Antoinette Brugman, tech editor of Bits&Chips.