Chronicles of Semiconductor Pioneers Chapter 5

Alex Zhou was a little surprised that he received a reply from Victor Hu the next morning.

You should know that twenty years later, Victor Hu checked his emails once a week.

"Does it mean that when teachers were young, they would check their emails once a day?"

"I didn't realize that the teacher back then was so hardworking."

Although Alex Zhou had followed Victor Hu before, at that age Victor Hu mostly just gave some directional advice.

Of course, even so, in 2016, when he was 69 years old, Victor Hu published a paper in Science that was cited more than a thousand times.

"Hello, Professor Hu. I am Alex Zhou, a sophomore student majoring in microelectronics at Yan University. I am Alex Zhou, a man who strives to reform the country despite its old state."

International calls are very expensive, and Alex Zhou did not open up new sources of information after he came.

Relying solely on scholarships is still quite insufficient.

"Alex Zhou, what a good name.

I originally thought it was the core of the chip.

I read the email you sent me and I thought it was some professor who had a new idea on MOSFET model.

Your results are good enough to be published in IEEE or even Science. "

The two of them spoke in English, and even when Zhou was an old country, its mission was to reform, Alex Zhou was also spoken in English.

After all, when he went to Berkeley to study for his doctorate, he specifically translated this sentence into English and said it when introducing himself to foreigners.

Zhou was a dynasty of China thousands of years ago. Adding this sentence instantly made Americans, who have little history, look at it differently.

This is also a little trick Alex Zhou uses to quickly get familiar with foreigners when he is abroad.

Talking about history and politics is one way to quickly get closer to a strange male.

"Yes, I am currently a sophomore student majoring in microelectronics at Yenching University. I am sending this email because I hope to study for your doctorate degree.

Because my financial situation is not very good, I still need you to provide a full or half scholarship. "

The difference between a full scholarship and a half scholarship in this era is that a half scholarship can get less money, and a half scholarship also requires work, such as substitute teaching, grading homework, etc.

If you receive a full scholarship, your supervisor will ask you to work, but you can choose to refuse.

Generally speaking, they will not refuse.

"International calls are a bit expensive for me, so I want to be direct in my message."

After Alex Zhou finished speaking, Victor Hu paused for a moment and asked:

"I will send you a test paper later and you will have five hours to answer it.

Please reply to me by email after you answer.

If you have 80 points, I will arrange everything for you.

This paper is not too difficult, it is just the standard for the doctoral entrance examination in the Department of Electrical Engineering at UC Berkeley.

Although it would be a bit difficult for ordinary sophomores.

But the keen intuition about the model and the way you handled it that you showed in the email are not what an ordinary sophomore student should be like.

Even many of the doctoral students I have supervised were not as capable as you in this area when they graduated. "

Victor Hu did not set a too high threshold for Alex Zhou as the entrance examination for doctoral students was difficult.

Of course, this is a difficult task for a sophomore student in China. No one except Alex Zhou can do it.

This is not a gap in level, but a gap in all aspects.

Whether it is the textbooks, teacher level, depth of learning, etc., there is a thick barrier between the sophomore year and the doctoral entrance examination.

Not to mention that you have to answer the questions entirely in English.

"What if I fail the exam?" Alex Zhou asked back on the phone.

Victor Hu smiled and said: "As long as you can prove that the email was written by you.

Then I will also help you with transfer and scholarship matters.

It just means you need to come to Berkeley to complete the courses you didn't take in undergraduate studies."

As a godfather in the semiconductor industry, who has spent more than 20 years at Berkeley, it is no exaggeration to say that it is easy for him to help students get scholarships.

Victor Hu admired Alex Zhou very much, not only because of the email, but also because of the honesty he showed in the communication and his fluent English.

Even some of the modal particles are the same as his.

During Alex Zhou's time in American, one of his main communications partners was Victor Hu. His spoken English improved dramatically during those years in American.

Of course, there are similarities between the two in their spoken expression.

Alex Zhou smiled on the other end of the phone: "Okay."

"The MOSFET model can relate Em to all device parameters and bias voltages. I described its use in explaining and guiding hot electron scaling. How did you come up with the idea of   interconnect modeling MOSFETs with predictive power from circuit simulation?"

The telephone lines span thousands of kilometers, and the distance between the two ends is not only geographical, but also temporal.

The answer Alex Zhou sent to Victor Hu was Victor Hu's own paper in 2000, which was published in the Proceedings of the 2000 IEEE Integrated Circuit Conference and ranked eighth in terms of citations among Victor Hu's more than 900 papers.

Although the ranking is not very high, it plays a connecting role.

Victor Hu's greatest contribution is the research and development and optimization of the 2D structure of semiconductors into a 3D structure, namely FinFET.

The basic planar (2D) MOSFET structure remained unchanged from 1960 until around 2010, when further increases in transistor density and reductions in device power consumption became impossible.

Victor Hu's laboratory at the University of California, Berkeley, saw this as early as 1995.

FinFET, the first 3D MOSFET, changes the flat and wide transistor structure to a tall and narrow one. The benefit is better performance in a smaller footprint, just like the advantage of multi-story buildings over single-story buildings in a crowded city.

FinFETs are also known as thin-body MOSFETs, and this concept continues to guide the development of new devices.

It stems from the realization that current does not leak through transistors within a few nanometers of the silicon surface because the surface potential there is well controlled by the gate voltage.

FinFETs took this thin-body concept to heart. The body of the device is a vertical silicon fin, capped by an oxide insulator and gate metal, leaving no silicon outside the range of strong gate control. FinFETs reduced leakage current by orders of magnitude and lowered transistor operating voltages. It also pointed to a path for further improvements: further reductions in thickness.

And current does not leak through transistors within a few nanometers of the silicon surface because the surface potential there is well-controlled by the gate voltage, a concept that was discovered after modeling MOSFET interconnects in the lab.

Alex Zhou couldn't possibly tell Victor Hu that you discovered this on your own.

However, since Alex Zhou has carefully read Victor Hu's most important papers, he has his own analysis of what he was thinking at the time.

These analyses were also recognized by Lao Hu during the communication with him 20 years later.