editor's blog
Subscribe Now

Laying n-Type Epi

Dopants used to be there just for their doping. But stress is now an important aspect as well, which means the dopant atoms must be sized appropriately as compared to their silicon hosts. This has worked for p-type, where compressive stress is desired. Germanium, which is larger than silicon, compresses the silicon, increasing hole mobility.

n-type should be the reverse: tensile stress is needed, meaning smaller dopant atoms. Phosphorus and carbon are both smaller and can work. Sounds simple, right?

Well, apparently not so. The n-type dopants have a tendency to migrate, and so far increased border security hasn’t worked. OK, kidding. About the security, that is. The migration has remained to be solved.

At Semicon West, Applied Materials announced that they had found a way to create a stable n-type epi layer. How do they manage it, you ask? Keep asking… they’re not telling. There was a mention of millisecond anneals helping to tweak any vagabonds before they get too far. And whatever they do sets up a strict thermal budget, although not so low that it affects the back-end interconnect processing.

Details aside, if this is all working as promised, then we have more control over how to optimize the performance of n- and p-type devices. You can read more in their release.

Leave a Reply

featured blogs
Sep 25, 2018
AWS (Amazon Web Services) released for general use its FPGA-based EC2 F1 instances in its cloud computing lineup in July, 2017. The EC2 F1 instance is based on Xilinx'€™s 16nm Virtex UltraScale FPGAs and people have been using this cloud-based hardware acceleration capabili...
Sep 25, 2018
Samtec is releasing new digital ECAD models for over 100,000 of its products on SnapEDA, the industry-leading circuit board design library. Traditionally, designers have spent days creating digital ECAD models – such as symbols and footprints – for each component ...
Sep 25, 2018
Robots are a hot topic these days. From helping doctors in the operating room to helping survivors of a natural disaster, it'€™s clear that robots are poised to play an important role......
Sep 25, 2018
CDNLive India took place a few weeks ago and we are just trying to catch our breath! If you missed it, I'm going to be posting two cool videos before the weekend with the highlights. Here are two blogs by the veteran blogger Paul McLellan - one on Asynchronous Design and...