Graphene to replace Silicon in IC fabrication

Silicon has been long used as the base to fabricate Integrated Circuits(ICs). But with the fabrication industry strictly following the Moore's law that packing density of chips doubles every 18 months, it won't be long before Silicon technology saturates. The signs have been seen and thus the fabrication industry is keenly searching an alternative as in near future we won't be able to increase the packing density of circuits based on silicon as it achieves saturation. One of the solution could be to use Graphene instead.

Graphene is a one-atom-thick planar sheet of sp²-bonded carbon atoms that are densely packed in a honeycomb crystal lattice. The requirement of any material to be used as substrate in IC fabrication is to have metallic, semiconductor and insulating properties either in free state and/or in compound state of that very material. The semiconductor nature helps in controlling the action of transistors(the building blocks of chips). The metallic property is needed to have high speed movement of carriers. The insulator quality is needed to isolate the transistors and also differentiate the on and off state resistance of transistors that need to have high variance.

The graphene sheet, rolled so as to form tubes, can act as metallic or semiconducting in nature based on the angle of rolling. The metallic nature of these tubes has long been appreciated by the fabrication industry. They have remarkably high electron mobilty at room temperature, with reported values in excess of 15,000 cm²V⁻¹s⁻¹. Also the mobility of holes and electrons are almost equal. The conductivity remains constant for a high range of temperatures. The semiconducting nature of graphene can be exploited by rolling the sheet at certain angle or by bending the tubes to an angle. This bending of graphene tubes decreases the conductivity at the bends and thus can be made to act as semicontuctor after some calculations. The only problem scientists were facing with graphene as a substitute of silicon was the insulating property of graphene which was very poor.

But , scientists in Manchester University have shown that graphene can be easily modified to act as an insulator by adding hydrogen atoms to its surface. The new material , called graphane, is made by exposing a graphene sheet to ionized hydrogen gas for some two hours. Until now, graphene was used to make transistors with other materials. But this process can't be used in IC fabrication due to the time and cost that comes with such processes. Commercially, this would fail. The need is of one material to be used as the base of the IC which can be then modified to act as conductor, semiconductor or insulator. Now, with this major successful experiment, graphene can be used as a subsitute of silicon. Also, this technology being new, would last for long time in the fabrication industry before it achieves its saturation. That means, it would be 10-20 years at least before we would start hunting for new material to substitute graphene for IC fabrication.

Thus, I see graphene substituting silicon in the ICs in the near future so as to fulfil the rising demand of higher speed of the market and to follow the Moore's law of doubling of packing density every 18 months.

Time for Change

Change, we can.....

-U.S. President Barack Obama

"Change" is a word feared by many. People prefer routines. We are very reluctant when it comes to changing our habits.


Talking about changes, the market scenario has changed drastically over few months. The government approach on the free market has changed. The trading systems have changed over time. We have moved from barter system to gold to money and now to virtual money(debit, credit, bonds, shares, etc.) . Sea levels have risen. Ozone layer has dropped. Population has increased over past centuries. The whole atmosphere has changed. Government have changed. Everything is changing. Change is infact inevitable.

The defination of power has changed from swords, guns and missiles to knowledge. The priority of all the nations has changed from military to economy. Pen has become mightier than the sword. And to this change in time and the environment, people have unwillingly changed themselves accordingly. Even the animals and plants have adapted. But, to this day, of there is one thing/species that hasn't changed that is we .."Nepalese". We are still stubborn to accept that we fear "change" the most. Maybe its because of the legacy our Gurkha ancestors have for bravery, we can't face the fact that we fear something i.e. change.

Days are gone when courage in battlefield meant everything. Days are gone when war used to be won with guns, cannons, missiles and khukuris. Now the war is won with economics and the market is the battleground. People in almost all parts of the world have accepted these facts and moved from learning sword-swinging to accounting and finances. And , talk about us. We stand tall and refuse to change ...refuse to accpet these changes. We still feel that we are born fighters. We still feel its in our blood and we still believe sword is mightier than the pen. Look at Japan and Germany. The people there were fighters too. But now, their pen speaks, their knowledge wins the war, and for the guns and swords..those rust in museums. People in the developed nations solve problems with dialouges, meeting , conversations.

We , in Nepal, still choose violence to solve every problem. All the decisions are made by the mob and laws passed on the streets. Be it some actor from neighbouring country saying that he doesn't like our country(no one verified this...totally based on rumours..), or some movie telling Lord Buddha was born in some other country, we have always gone to the streets for solutions and burnt our mother Nepal to pacify ourself. May be to "demonstrate" that we have won....Won what?..i don't know..

Well may be to show that we are the decendants of the fierce Gurkhas. Maybe to show the world that we are still brave..errrr.. may be we are still fools as pointed out by our Maha Kabi Laxmi Prasad Devkota. We show pride in burning shops and devastating the economy. Convesations and dialouges are always lower priorities while solving issues. Violence is the defacto choice.

Maybe we are too immature when it comes to dealing with situations. Or, maybe we still believe that sword is mightier than pen. Maybe Khukuri still rules for us. It is not that we lack brilliant brains in Nepal(Nepalese have shown their brain-power in almost all fields in the world), it is because we are afraid of change. ....change in our approach to solve problems ...change the way we live....change the way we show our courage..

When the whole world is talking about change(remember ....Change, we can.....), we still fear it. Fears of having no strikes....fears of having no bandhs...fears of being governed by proper administrators...fear of not having the mob rule which we enjoy ....fear of not being able to decide things on the streets.

Well, dinasaurs didn't accept the idea of change..the idea of adaptation, so they are extinct now. The cockroaches adapted to the environmental change, so they still have their decendants living. We have to realise this fact and understand that Khukuris can't win the war for us. We must be proud of our past and also realise that we have to change our present if we are to be in the future. We have to start giving importance to knowledge. We have to start using our thick heads rather than use tyres and bricks. We have to use tourches to light the houses ...not to burn them. We need to change so as to build our economy rather than doom it. We need to accept and acknowledge the power of knowledge. We need to adapt to the changing time. We need to change. Only then, we will have a future or else just like the damn stubborn dinasaurs, we will be extinct too.

Change, we must....
-Unknown