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Celebrities die e at a time and Changing the Transistor Channel


Soren Sandmann Pedersen, Impulse Train, Celebrities die 2.7182 at a time, here.

Rather than trying to define exactly what constitutes a celebrity, I’ll simply assume that they die at a fixed rate and that they do so independently of each other (The Day the Music Died notwithstanding). It follows that celebrity deaths is a Poisson process with intensity λ where λ is the number of deaths that occur in some fixed time period.

As an example, suppose we define celebrityhood in such a way that twelve celebrities die each year on average. Then λ=12/year, and because the time between events in a Poisson process is exponentially distributed with parameter λ, the average time between two deaths is 1/λ = 1/12th year, or one month.

Richard Stevenson, IEEE Spectrum, Changing the Transistor Channel, here. Gallium Arsenide is back.

Now chipmakers are adapting this basic strategy to make a more drastic change: the wholesale replacement of the silicon channel. A few materials have emerged as front-runners for the two kinds of transistors needed for logic circuits. For the positive-channel field-effect transistor (pFET), which carries holes across the channel, the leading candidate is germanium, which sits just below silicon on the periodic table and can transport charge four times as fast. For the negative-channel FET, or nFET, which depends on the movement of electrons, engineers are considering a mix of elements from groups III and V of the periodic table. One of the most promising is indium gallium arsenide (InGaAs), which boasts an electron mobility of about 10 000 square centimeters per volt second, more than six times that of silicon.


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