Quiet chaos

Researchers in France have investigated the performance of high-permittivity (high-k) 28 nm CMOS devices in comparison with the standard 45 nm technology. They have shown that power output is increased in the smaller device, even for lower bias voltages. Reducing the gate length of these devices will have the effect of increasing the leakage current. This is due to the fact that a smaller structure will be more affected by tunnelling from the device into the reservoir or substrate. High-k CMOS was originally designed to overcome the consequent increase in DC power consumption. However, the smaller structure does suffer from a reduced maximum operational frequency, caused by a degradation of the device´s gate resistance. This means that the technology will be difficult to implement in standard radiofrequency systems, which will be an important challenge for the future.