I’ve recently returned from the International Workshop on Junction Technology in Shanghai China. Shanghai is a fascinating city (or mega-city). The Chinese say that Xian is the city of the past, Beijing is the city of the present and Shanghai is the city of the future. I certainly agree with that characterization of Shanghai! From the LED-dominated night skyline to the new high-speed maglev train – Shanghai truly is the city of the future.
(Picture from left to right is Sadanand Deshpande of IBM, Raj Jammy of Sematech, Kelin Kuhn of Intel and Yun Wang of Ultratech).
The International Workshop on Junction Technology (IWJT) is a critical conference for the implant and annealing community. Why do we care? Well, in a modern CMOS device, one of the most critical parameters for improving performance is the parasitic resistance from the channel to the contact (see Figure, left). This parasitic resistance is the sum of Racc (the resistance in the source-drain extensions) + Rspreading (the resistance as the current fans out into the epi + Repi (the bulk epi resistance) + Rinterface (the resistance between the epi and the silide) + Rsilicide + Rccontact. IWJT primarily focuses on improving three of these resistance components, Racc, Rinterface and Rsilicide.
Racc is the resistance of the source-drain extension. The percentage impact of Rext has been increasing each generation (see Figure, left). Rext is a very sensitive function of the implant and anneal technology. The goal is to achieve the possible junction depth (XJ) with the lowest possible resistance (Racc). This is achieved by improvements in implant and anneal technology.
One of the highlights of the conference was the vigorous discussion on molecular implants (see Figure, left). The key idea with molecular implants is to use a large (or very large) molecule to improve the amorphization, reduce the penetration and increase the dose of the implant into the substrate. One molecular implant (BF2) has been around for a while – but the industry is increasingly moving to much larger molecules such as decaborane, octadecaborane, and carborane. While a number of talks discussed molecular implants, the keynote by Anthony Renau, the modeling study by Takaaki Aoki and the invited paper by Wade Krull all focused significant discussion on the benefits and challenges of molecular implants.
Another of the highlights of the conference was the focused discussion on annealing technology. The key idea with modern annealing technology is to activate the implant with as little subsequent movement of atoms as possible (see Figure, left). While a number of papers discussed anneal technology, the invited papers by Lee on long-mS flash anneals, and Wang on laser annealing all focused significant discussion on the challenges facing anneal technologies in the coming generations.
While I was in Shanghai, I had the opportunity to visit EXPO 2010 for an afternoon and evening. While I can ramble on indefinitely about the various displays and pavilions, my major geek take-away was that Shanghai must have bought out the market on LED technology. After dark, EVERYTHING seemed to be lit up with complex programmed light shows. It was virtually impossible to take a bad picture.
Stay tuned. My next blog (mid-July) is on VLSI!
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