# Happy birthday Mr. Electron!

Well… at least if we can refer to one of the latest tweets from Imperial College, J. J. Thomson announced the discovery of a particle with a miniscule size, negative in charge, and yet smaller than an atom. All during a regular Friday lecture at the Royal Institution on 30 April 1897!

So this means that Mr. Electron is hitting his 120s today! Hurray, electrons in my computer! I wish I could make it up to you with a cake, but I don’t really know where in spacetime you are right now.

Oddly enough, Thomson’s experiment provided an extremely accurate ratio between the charge and mass of the electron, even for today’s standards.

Greetings too, to all electronics engineers – our titles contain bits of two of the most influential 19th century discoveries! Could today be marked as the day of electronics?

Finally here’s how electron guns are made… Meh, don’t you think that people had a rather odd taste to magazine covers back in the day…

Sealing electron gun assembly – recklessly stolen from pulp librarian’s cover archives.

# How long are your wires?

Lately I have been busy working on my analog to digital converters, I have gotten up to the phase of laying out the transistors and interconnect. A question struck me – how long are my wires? I mean, the total sum of lengths of all my wires? Usually the average bus length does not exceed a few hundred micrometers before the signals are being re-buffered, but we have hundreds, if not thousands of them sometimes. To illustrate what I mean, let’s have a sneak on my chip’s interconnect:

Here are a few of the metal layers shown separately. Sorry, can’t afford to show you the rest of the system and more than the metal layers as it’s still a secret, shhh… : )

A close view of vertical interconnect

Vertical interconnect

Horizontal interconnect

A close view

Horizontal interconnect two

Considering the fact that some SoCs can have up to 16 metal layers, we can continue our list forever. Notice the ruler showing the scale of the first figure, the unit is in micrometers. I was wondering what is the best way to calculate all sums, however Domenico Pacifici has done this analysis in his PhD thesis before me and I dare to reprint one of his figures.

Total interconnect length in km/cm2 vs year of process development

Wowsh, I had guesses that it may be in the order of hundreds of meters, but 10km? Also notice the log scale, nicely matching with Moore’s law. Remember also that in 2008 the cutting-edge process nodes were at about 90 to 65nm. Some large SoCs may reach areas of about 5 $cm^{2}$, this means that the computer chips we have in an average town contain enough wire to probably reach the Moon? Impressive! Now keep calm and continue pushing polygons!

# One place for science in Oslo

Greetings from Norway! I paid a visit to Lukasz and some former colleagues last weekend so I thought “Why not write a post (or a series of posts) about places for science in various cities?”. Here is where I start – the University of Oslo or to be more specific the Department of Informatics and Mathematics and to be “Swiss sharp” – the Nanoelectronics group.

The University of Oslo is one of the largest higher education institutions in Norway being the biggest in number of students in social sciences. When it comes to natural sciences it has a pretty strong competitior namely the Norwegian University of Science and Technology in Trondheim. Nevertheless, the Department of Mathematics and Informatics has a number of applied science research groups, in addition to that the pure theoretical maths and physics groups do not fade-out too much in the overall picture. The main campus (Blindern) is also merged with Oslo Science Park and dozens of applied maths/informatics private or public companies e.g. one of the major being Sintef. Besides mathematics and informatics as a “Si person” I should also mention something about the semiconductor/applied physics opportunities in that place. Unfortunately when it comes to microchips there are only a few spots in Oslo doing design, these few “spots” however on the contrary have a long history (in the context of the semiconductor industry) e.g. Texas Instruments c.a. 13 years and nowadays OmniVision (before Photobit – Micron – Aptina) about 15 years old. Some rumours about Nordic Semiconductor opening more positions in Oslo have been spreading with the speed of light recently too. Speaking of applied physics a mini-cocktail of small companies in microfluidics, optics, and nanomaterials exist, but maybe someone with broader experience should hint what actually the situation is.

Anyway, I aim to give a virtual tour of the Nanoelectronics group at IFI in UiO and provide you with some “live” pictures from my ultra-high noise, low dynamic range and shaky camera.

First stop – Department of IFI (Institutt for Informatikk) or as I often like to call it – “THE MOTHERSHIP”!

The Mothership

IFI – Department of Informatics @ UiO (typical Scandinavian weather)

This place is vacated by an extremely large number of research groups, here’s a link providing an alphabetically ordered list of all research groups at the department.

Apart from research groups, the first and second floors of this building are tailored for students offering all sorts of lecture halls and individual study rooms which one can book online. I really like the idea of giving names to rooms instead of using boring number-based systems, it seems like all Scandinavian universities I have visited so far follow this system and it is maybe something to consider by some institutions in the rest of Europe. It’s more fun to have laboratory exercises in e.g. “Olympen, Asgård, Egypten, Southfork, Muxen, Ada, Touring, Hopper, Mead, Volt, Kepler or Schrodinger” than “2.210, 4.311, 10.304, C.53 or 7.777 (:”.

a Practical Extraction and Reporting Language

After BASIC, my first ever official program used Pascal

This place is Chilly like Norway

Caml – humpy as a camel’s back ?

C – I see

Xml – eXtensible markup language? I am sure you can do better with PERL

Awk – hates PERL but both go out for dinner from time to time together with bash and tcl (;

“Master! Master! Where’s the dreams that I’ve been after?”

Limbo? Hell’s edge, or?

The baroness of all programming languages, ever!

They have even built a room dedicated to our blog, oh such an honour.

Kappa – the 10th letter of the Greek alphabet?

Photons hit electrons, but not before they’ve passed though the optics.

And the corridor & rooms goes to infinity

Ok, pretty lengthy, but the child in me screamed out so I had to take pictures of the room nameplates. Follow me to the 5th floor which is occupied by the Nanoelectronics group.

At the entrance we are greeted with some posters.

“The gods must have gone crazy” – stacked games, stacked sandwich, stacked chips 🙂

“We are the robots, we’re functioning automatic and we are dancing mechanic…”

This is what oil leads to – you guys need two more, this is not enough.

The average PhD’s heaven! Just give me coffee and a white board.

Lukasz’s messy desk – messy = work

And a poster of his master’s thesis

Chips chips chips 😉

And more chip (ship)s’

Dungeon and no dragons

The anechoic chamber!

Echoooo

Can you hear my heartbeat?

Network analyzers, but wait, what do we need them for?

Of course, to measure a random cable’s rf medium quality, handy!

Smells like electronics

Lukasz’ master thesis – the bio-inspired image sensor

And its camera control board

And a color wheel for testing purposes

Another angle (now I am really starting to suffer from comment idea deprivation)

The new testing furnace. We used the old one to bake a frozen pizza but it didn’t go very well. I wonder why? The fire-fighters were not quite happy to visit us, nor the departmental head. Dear readers, in case you want to bake a pizza in a temperature testing chamber make sure you have set the right temperature profile for your pizza indicated on its package. Alternatively you may want to try with cookies as well, what could possibly go wrong?

A microprobing station for emergency chip surgeries.

A c”s”hip. Hint, Swedes pronounce ch as sh (accent) so, if you say so – it’s a ship.

And another emergency room

Accompanied by some chip pulse and health monitors

And some other randomly scattered scalpels.

A PCB printer, I wish I had one at home some years ago

With this my shaky virtual tour ends. Unfortunately the trends point that chip design loses more and more popularity amongst students (not that it has been an extremely popular science to start with but…) as opposed to computer science, physics or mathematics. So hopefully this tour would inspire you to go forward and dive into the endless river of microelectronics.

# The cost of knowledge?

Not very related to the scope of our blog, but still… Why do companies keep the knowledge to themselves and try not to spread it out as much as possible? Well, one might argue that otherwise they would lose the game versus the rest of the competitors in the jungle, in which they might be right. We do not live in an ideal world, I know, but I imagine, one day, a world without patents, without proprietary technology and even physical phenomena. How can combinations of a few physical phenomena be proprietary at all, e.g. the case with some military applications we know from the past (hint. 1945)?

Unfortunately universities can not keep up with developing new technologies and revealing what industry discovers and implements daily, which, apart from teaching is probably their second role of most importance to the society. Just imagine a world where all universities and companies share their scientific discoveries?! The scientific competition, I imagine, would be much much higher, yes it would be tougher to compete, but in such a world the scientific advancements would rush-up at a higher pace too. Too many groups are re-inventing the wheel nowadays due to either “proprietarism” or “non-bother-to-publisharism”, if we can learn from each other’s mistakes, I imagine the function of development progress would shift from linear towards… still linear but with a higher slope dy/dx.

Back to why I am writing this, there is a conference in CMOS Image Sensor technology occurring yearly, which attracts a lot of major image sensor design companies (the people who hold most of the knowledge in our vision sensor field). My point and anger? (not really?) is that this is a workshop oriented towards the very same design groups organizing or helping out the organizers, so knowledge (if one can speak about knowledge in the case of this conference) is somehow proprietary again. In such a place one goes to sniff around for opportunities to meet “highly ranked” (as the ad says) people and try to squeeze out as much as possible for what they are trying to do during the late evening dinner while all “major” attendees are drunk. Possibly the speakers also get another “free” day off which they may quite enjoy and in general giving such talks is indeed an interesting task. It is great that such conferences exist, meeting people from your own field is definitely a pleasure, but at such price this makes it a vicious circle and we again end-up having industrial-only attendees. Here is a quick reference to what level of craziness I am referring to:

IS2015 costs per attendee

Why not be a bit more open when it comes to knowledge? What do you think?

# Energy in a cup of coffee

First day in the lab after some lengthy Christmas holidays! Almost a little bit too much. A proper way of starting the day means sharing a cup of coffee with my fellow lab rats. I love morning espressos in my favorite cup, hijacked virtuously from my previous job by means of polite mooching, yippie. 🙂

A double espresso in a huge cup.

Long time no espresso for me meant burning my tongue at the first sip, and hence this post. Can the “invested” thermal energy in a double espresso kill me if it was to be transformed into gamma rays? I offer you here some of my ultra-primitive (8th grader’s) random morning nonsense thoughts.

• We can assume that coffee is water (oh what an irony) and therefore its specific heat would be 1.0 cal/g.degC i.e. same as water.
•  Because something annoys me with the unit of calories, let’s convert it to something more useful as e.g. jouls:

$1 cal = 4.184 J$

•  The volume of a double espresso equals the volume of two single espressos (WOW!) which therefore is 60 ml, let’s also assume that 60 ml of coffee weighs 60 g to make our life simpler.
•  Tap water is 20 deg C and a properly extracted espresso should be around 75 deg C, thus we have a delta of 55 deg C to “invest” in it. The energy required to get this precious liquid will be:

$55 \textdegree C \times 60 g \times 4,184 J = 13807,2 J$

Gray (Gy) is unit measuring the absorbed by a body ionising radiation which is defined as:

$1 Gy = 1 \frac{m^{2}}{s^{2}} = 1 \frac{J}{kg}$

We can thus very easily convert the energy required for heating the coffee to an absorbed radiation dose which would be:

$\frac{13807,2 J}{70 kg} = 187 Gy$

I use 70kg here as that’s the closest to an average person’s weight. So how much is 197 Gy? According to this wikipedia table, and assuming a 100% absorption rate 197 Gy would pretty much kill me within 24 hours. This is of course provided that we have 100% absorption rate. Other more accurate absorption models exist however, I’ll skip this for the time when humanity discovers what exactly black holes are…

If all my simple thoughts above are correct this happens to be a fairly scary fact. Hmmmm, another less deadly question pops-up to my mind. Can the very same energy kill a microchip if it is in the form of a focused (0.1mm) laser beam with 600nm wavelength projected onto the surface of a silicon die with Al top metal layer thickness of 8000 Å and assuming no passivation layer has been deposited on top???

# Greetings from Germany!

Desi here, just wanna say I’m still alive… And happy new year! May it be another jolly year of circuit building, signal processing and photon-electron action!

I greet you from Berlin with this fabulous display of electricity and light:

As stated in our very first post, I am currently proving that I am not a robot by having a vacation of sorts. However, I will be back quite soon and I’ve even prepared a little surprise. Here in Germany I discovered the miracle of Conrad: a dream store for every tech geek out there. Today I prepared the wires from the tiny electronics kit I had bought. Just a teaser for what’s going to occupy my time and mind in the next couple of days…

Of course, a blog post with my project will be published as well. Soon!