ibm has demonstrated a silicon-germanium (sige) transistor that operates at 350ghz. this transistor is 300% faster than current devices, and 65% faster than previously disclosed transistors. sige may soon replace gallium arsenide and indium phosphide compound materials in communications chips, and ibm hopes that this will lead to 150ghz integrated circuits (ics). gallium arsenide and indium phosphide have higher electron mobilities than silicon, but are much harder to work with. germanium is added to silicon to increase switching speeds. potential applications for ibm's chip include radar detection systems and high-speed lans, and various other system on chip (soc) designs. it is unlikely, however, that sige microprocessors will ever become common. germanium is a semiconductor that was extensively investigated four decades ago, but by the early 1960s it had lost out to silicon. ibm has demonstrated the chip, but it won't be in production until 2005-2006.
rob's note: keep in mind that this is a very different class of chips than the p4s and athlons on your desktop, and the ghz ratings don't correlate to the same type of performance or applications. still, it's nice to see how fast things could go … current technologies look like they are at 110ghz, with even ibm's 180-200ghz devices slated for production next year, not now.
user comments 23 comment(s)
|isn't there… (12:57pm est mon nov 04 2002)
seriouly,scientifically, a speed limit ? – by da
|sander – clarify (1:25pm est mon nov 04 2002)
is it a fast chip, or just a single fast transistor? i'm having trouble discerning which from the article. – by freezebrothers
|diamond and a few high bg trinary compounds… (1:25pm est mon nov 04 2002)
da – da!
physics of it all:
electron mobility is now in the 'balistic' regime, where lattice scattering is an insignificant component fo device physics. bandgap determines energy of electrons and holes. but doping determines junction injection velocity. so, in theory higher bandgap semiconductors “go faster”.
oddly, ge has a lower bg than si. sige must form a quartenary regular molecular lattice which strains ge enough to increase bg. also solves problem with ge's wickedly low melting point. pin those atoms down, ya!
but in the end, the 4.2ev bg of diamond, coupled with its outrageous phonon (not photon) mobility will probably be the speed winner. some dope (pun intended) told me a few years back that 25,000 ghz diamond trannies should be possible at the 0.01 micron level.
safe to venture that that's a bit out there though.
– by goatguy
|this will boost cpus (1:54pm est mon nov 04 2002)
of course we won't see 350 ghz cpus, but if cpus used this technology i am sure they can squeeze out at least 50-75 ghz. but physics is reaching a limit and we will probably see a trend towards more work per cycle as opposed to more cycles – by jd
|goatguy (2:51pm est mon nov 04 2002)
i wanna hire you for my new company. you seem to be very much into details of everything. most importantly, you seem to be efficient, efficient, and steadfast in all those boring technical terms. you'll be perfect as an engineer doing all the dirty work for my company!
how much do you want to get paid hourly? $10 or $15 without benefits? – by affez pow
|goatguy probably makes more! (4:25pm est mon nov 04 2002)
goatguy, i never understand anything you say! i am twelve years old and i want to learn all you know. can you give me some resources from which i can learn this outrageous material please? i am astounded by complicated things such as those you speak of. – by sigesamurai
|transistors fave two jucntions, (2:30am est tue nov 05 2002)
diods only have one. i've seen several variations of and gates using diods instead of transistor.
would a sige diod in this process have a faster switching time then a transistor of the same process?
would a diode rom based adder with 7 junctions between input and output clockfaster then one with individual tranzister gates? – by zarcondeegrissom
|ps3 (5:21am est tue nov 05 2002)
is it me, or just a coincidence that this technology is due to be in production around the same time that the playstation 3 is due to be released? – by anon
|diods vs transistors cont… (5:55am est tue nov 05 2002)
i made a picture…cool
the top one is a binary-to-single-hot converter tied to the proper outputs with diods to prevent curent going the wrong way. the bottem is a commen textbook full adder using transisters. – by zarcondeegrissom
|maby this will work… (5:59am est tue nov 05 2002)
– by zarcondeegrissom
|haaaaaaaaaaa you've beem hacked (9:14am est tue nov 05 2002)
antigone’s sister ismeme is reluctant to help her sister. she feels that her antigone’s crusade is not worth fighting for. ismeme will fallow creon every command she knows her place in society. ismeme is the trying telling the end to dissuade antigone from disobeying creon wishes. at the end of the play ismeme wants to die with antigone because she learns of that antigone was right and that you should fight for what you believe in even if you have to die for it.
haemon he is the son of creon and only popes in twice in the play. the first time he is in it antigone rejects him. then he becomes her fiancé the second time he is in the play. haemon dies for antigone to show his father that he was wrong. haemon thinks that his father should be lenient with his fiancé.
tiresias is the blind prophet he tells creon that he is decreasing his family by not letting her burry her brother. tiresias tells the truth that no one wants to hear. him being blind and seeing prophecy of what is to come shows that every one that does not lesson is blind to. no one lessons to tiresias when it is about them because the truth is not what people want to hear. tiresias is not on any one side but the gods he pledges his alleges to them.
– by coronel xander
|ahahahah (9:15am est tue nov 05 2002)
creon is a very powerful man that strikes fear into man with the sound of his voice. he rules with a stubborn blindness that will lead to him being alone in the end. he will not head the words of tiresias and lets his niece die in a cave. creon blindness leads to the death of he own son but creon could care less as long as he is right. his wife eurydice dies just because of her being told to by the chorus. all his wife does in knit in her room tell it is time to die. at the end of the play he realize that his ways were wrong and tries to change them but it is too late.
antigone is the tragic heroine in the play. she is not like her sister who is fine with her place in society. she wants to give her brother a proper burial. creon said that he was a traitor and decreased his family. antigone thinks he fought for what he thought was right. she is also a little rebellious of a child but this gives her a reason to stand up for what her and others believe in. she is willing to die for the cause.
|is it just me… (9:34am est tue nov 05 2002)
or is coronal a loon? – by chicken, tastes like
|euh… (9:54am est tue nov 05 2002)
in the sige, ge is used to replaced the doping by electro migration. nowadays, doping are maid by bombarding silicium. this introduice some defect inside the silicium cristal. those defect slow down electron.
so using ge avoid the defect.
the problem is that ge only add doping for one charge type (+ or – i have forget it). so you only could do, one type of transistor (npn or pnp) but cmos needs both. so you could only do bipolars transistors or one type of mos transistors for hf technologie has it is use today for asga and inp. – by nico
|ahem… (11:22am est tue nov 05 2002)
si & ge (and c and sn(tin) and pb(lead)) are in same iv group on periodic chart of elements. this (and research) implies that they are half saturated. adding si to ge, ge to si or any iv to any other iv doesn't dope the semiconductor either towards surpluss or deficit electrons. still takes the iii-v group or the heavier ii-vi series.
– by goatguy
|not a doping ! (11:39am est tue nov 05 2002)
that's not a doping !
there is a layer of ge and then a layer of si.
the difference is in the level of energy. that's semi-conductor. this difference push the remaining charge inside the si, that's how it's work. – by nico
|please go reseach “pn junction” (4:17pm est tue nov 05 2002)
sorry, but i tire of this. no matter how or what you call it, useful semiconductors are characterized by …
 a substrate of 1/2 filled molecular units (either si, ge, gaas, inp, …)
 doped with either electropositive or electronegative impurities (in, p, n, as, b, se, …)
 separated by structures that allow the flow from a to b to be constricted by the influence of a field on a gate g.
whether npn, pnp, jfet, mosfet, smicfet, or whatever… the above 3 rules apply.
si-ge doesn't change rule  in any way, except to strain the pi-electron bonding between adjacent atoms. a true quasicrystal.
oh well… this'll probably get flamed for being overopaque.
– by goatguy
|goatguy (12:39am est wed nov 06 2002)
i agree that wire interconects will be around for a while.
do diods switch faster then transisters? is it twice as fast for having half the junctions or less? – by zarcondeegrissom
|diodes & switching time (9:04am est wed nov 06 2002)
diodes switch between conducting and insulating modes very quickly (depends on junction capacitance, source current available for reversal and electron::hole recombination dynamics). very thin, very small (100 nanometer) devices can switch in picoseconds. that's on the same order as these trannies.
but diodes are dumb. they leak, they have on-to-off hysterisis, they're sluggish in one direction, they consume power, and worst of all, they don't amplify. see, amplification is the underpinning of all non-trivial logic, since devices need to cascade to others in curious and crafty ways.
btw, 'way back in the early 60's (well, all the way through about '68 to be exact) you could buy “dtl” or diode-transistor logic and and or gates. but they were [slow, leaky, hysterisis…] compared to the then-claimant to the throne “ttl” (transistor-transistor logic). all these were squeezed out by the ridiculously slow cmos logic. but cmos's speed-power-product would ramp vastly better with scaling than ttl. today's ghz cpu's seem to prove that point pretty handily.
– by goatguy
|danke schön goatguy (6:53pm est wed nov 06 2002)
so a basic adder using cmos (triplegate or not) would out clock a adder using transisters (or cmos) for input & output amplification and diods for the basic logic and functions. and the mosfet design would be more predictable with it's output charicteristics. – by zarcondeegrissom
|oh you guys… (12:43am est thu nov 07 2002)
germanium can be implanted into the silicon lattice and then annealed to 'erase' crystal defects. germanium serves to increase si-si bond distance (aka 'strained' silicon) and thereby increase elctron mobility. the ibm article is certainly referring to 350 ghz as the 'intrinsic' switching speed of the sige transistor. intrinsic speed is how fast a single transistor can go from on to off when built into a simple oscillator circuit. this means the transistor is not chained down to 100 million other transistors in a logic chip and all 100 million forced to 'stay together' more or less. a logic circuit must keep many transistors in synchronicity with each other while following a cadence and rythm (clock cycle). it seams that there is a certain ratio between the intrinsic transistor speed and the max speed of a logic circuit (depending on the # of stages in the pipeline). for the current p4, that ratio is around 50 i think. what that means is a 350 ghz transistor could allow for a 6 or 7 ghz logic chip. on the other hand, these days the rlc (resistance/inductance/capacitance)
delays of the metal lines is the biggest bottleneck for chip speed, so building a p4 using today's # of metal lines and interlayer dielectric material – but with 350 ghz transistors instead of 150 ghz transistors – wouldn't win a significant gain in chip maximum speed. you should all read stuff on intel's website ( go to then in their search box try “silicon showcase”) about 1) the so-called” terahertz” transistor, and 2)the upcoming 90nm process that is on target to sell product in 2003. one particular pdf document tells a lot of info on transistors, metallization and interlayer dielectric schemes that has already made the 90nm prescott a reality in the labs. – by super goat
|ins1-final project rubric (5:13pm est sat dec 27 2003)
i was wondering what compounds/alloys
does a germanium element have?
please soon cause i need this done by the time we go back to school which is january 5,2003.
|suck (11:44pm est sun jul 02 2006)
aa – by cock