Vanishing Transistor essays

Vanishing Transistor essays The article The Amazing Vanishing Transistor Act found in the IEEE Spectrum discusses some of the new technologies that can be implemented for the transistor to increase its performance. Reducing its size can make the channel distance decrease causing the charge carries to have a shorter distance to travel. However, when reducing the size of the channel the gate has a harder time turning the channel off due to the lower threshold voltage that allows the carries to flow without a bias voltage. The first technique discussed to improve the transistor is to strain the silicon by replacing some silicon atoms with germanium atoms. This causes the distance between atoms to increase due to the germaniums larger size. The size change in the lattice changes the energy band structure along with reducing electron and hole collisions and decreasing their effective masses therefore increasing mobility. When the mobility increases, it allows for carriers to be more quickly accelerated by an electric field. This method isnt currently in production since if implemented on the current etch process (SOI), the smaller energy gap will cause more carriers to leak into the substrate. This would drive the power consumption up due to current being drawn but not used usefully. The best way to stop gate leakage is to increase the gate insulation with a material that has a higher dielectric constant. Currently, hafnium dioxide is being researched and appears to be the best candidate even though it appears to degrade carrier mobility. Hafnium dioxide gate insulation was combined with a strained silicon substrate and the two are compatible together. It appears this combination is able to have high mobility with low gate leakage. When the transistor continues to shrink its difficult to maintain a strong connection between the channel and gate with the current polysilicon gates. The highly doped polysilicon acts nearly ...