Zhou Xin was a little surprised that he would receive a reply from Hu Zhengming the next morning.

You must know that 20 years later, Hu Zhengming checks his email once a week.

"Could it be that when I was young, my teacher would read my email once a day?"

"I can't see that the teacher was so hard working back then."

Although Zhou Xin followed Hu Zhengming before, Hu Zhengming only gave some directional advice most of the time at that age.

Of course, even so, in 2016, when he was 69 years old, Hu Zhengming published a paper with more than 1,000 citations in Science.

"Professor Hu, hello, I am Zhou Xin, a sophomore majoring in microelectronics at Yan University.

Transnational calls are very expensive, and Zhou Xin did not open source them again after he came.

Relying on scholarships alone is still quite stretched.

"Zhou Xin, good name.

I thought it was the core of the chip.

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

Your work is good enough to be published in IEEE or even Science. ”

The two spoke in English, even though Zhou was in the old state, Zhou Xin also spoke in English.

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

Zhou was the dynasty of China thousands of years ago, and adding such a sentence instantly made the Americaniks, who had no history, look at it differently.

This can also be regarded as a little trick for Zhou Xin to quickly get familiar with foreigners abroad.

Talking about history and politics is one of the ways to quickly get closer to another strange man.

"Yes, I am currently a sophomore majoring in microelectronics at Yenching University, and the reason why I am sending this email is to come and study for your PhD.

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

The difference between the full award and the half prize in this era is that the half award can get less money, and the half award requires work, such as substitute teaching, homework correction and other work.

Full awards will be asked to work by the tutor, but there is an option to decline.

Generally speaking, there will be no refusal.

"International calls are a bit expensive for me, so I want to be straightforward."

After Zhou Xin finished speaking, Hu Zhengming paused for a moment and asked:

"I'll send you a paper later, and you'll have five hours to answer it.

You replied to me by e-mail after you answered.

If it's eighty, I'll arrange everything for you.

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

Although for the average sophomore, it will be a little difficult.

But the intuition you showed in your email about the model and the way you handled it were not your average sophomore.

Even many of the PhD students I have taken are not as capable as you in this regard when they graduate. ”

Hu Zhengming did not set too high a threshold for Zhou Xin, the difficulty of the doctoral entrance examination.

Of course, for sophomores in Huaguo, this difficulty can't be done by anyone except Zhou Xin.

This is not a gap in levels, but a gap in all directions.

Whether it is the textbook, the level of teachers, the depth of learning, etc., there is a thick barrier between the sophomore and doctoral entrance exams.

Not to mention that you have to answer in English.

"What if I don't pass the exam?" Zhou Xin asked rhetorically on the phone.

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

Then I'll help you with transfers and scholarships too.

It's just that you need to come to Berkeley to make up for the courses you didn't finish in your undergraduate studies. ”

As the godfather of the semiconductor industry, he has spent more than 20 years at Berkeley and wants to help students get scholarships, which is no exaggeration to describe it as easy.

Hu Zhengming admires Zhou Xin very much, not only because of the email, but also because of the honesty shown by the other party in communication and this fluent English.

Even in some of the modal words, he is the same.

During Zhou Xin's time at Ameriken, one of the main communication objects was Hu Zhengming, and his spoken language mainly improved by leaps and bounds in the years of Ameriken.

Of course, there will be similarities between the two in terms of oral expression.

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

"How did you come up with the idea of modeling MOSFETs interconnects through the predictive nature of circuit simulation, as the MOSFET model can correlate Em with all device parameters and bias voltages, describing its use in interpreting and guiding thermoelectronic scaling?"

Across thousands of kilometers of telephone lines, the two ends are not only geographically distanced, but also temporal.

Zhou Xin's answer to Hu Zhengming was Hu Zhengming's own paper in 2000, which was published in the proceedings of the IEEE Conference on Integrated Circuits in 2000, and ranked eighth in the number of citations among Hu Zhengming's more than 900 papers.

Although the ranking is not very high, it plays a role in connecting the previous and the next.

Hu Zhengming's biggest contribution is to develop and optimize the 2D structure of semiconductors, that is, FinFET.

From 1960 to around 2010, the basic planar (2D) MOSFET structure remained unchanged until it became impossible to further increase transistor density and reduce device power consumption.

Hu Zhengming's lab at the University of California, Berkeley, saw this back in 1995.

FinFETs, as the first 3D MOSFETs, changed a flat and wide transistor structure into a tall and narrow transistor structure. The benefit is better performance in a smaller footprint, just as a multi-story building has over a single-story building in a crowded city.

The concept of FinFETs, also known as thin-body MOSFETs, 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, where the surface potential is well controlled by the gate voltage.

FinFETs keep this thin-body concept in mind. The body of the device is a vertical silicon fin covered by oxide insulator and gate metal, leaving no silicon outside of the strong gate control range. FinFETs reduce leakage current by orders of magnitude and reduce transistor operating voltages. It also points to a path for further improvement: further reduction in thickness.

The current does not leak through the transistors within a few nanometers of the silicon surface, where the surface potential is well controlled by the gate voltage, a concept that was discovered after the MOSFET was replicated in the lab for interconnect modeling.

It is impossible for Zhou Xin to tell Hu Zhengming, this is what you found out yourself.

However, because Zhou Xin has read Hu Zhengming's most important papers intensively, he has his own analysis of how he thought at that time.

These analyses and the exchange of Lao Hu twenty years later have also won the recognition of the other party.