US researchers have cast doubt on the elastic tunnelling model for transistor noise.
"The model was a good working theory when transistors were large, but our observations clearly indicate that it's incorrect at the smaller nanoscale regimes where industry is headed," said scientist Jason Campbell of the US National Institute of Standards and Technology (NIST)
The theory predicts that as transistors shrink, noise fluctuations should correspondingly increase in frequency.
However, Campbell's group claims that even in nanometre-sized transistors, the fluctuation frequency remains the same. "This implies that the theory explaining the effect must be wrong," said Campbell.
According to Campbell, the noise he is working on also increases as power reduces in the device.
"This is a real bottleneck in our development of transistors for low-power applications," he said. "We have to understand the problem before we can fix it - and troublingly, we don't know what's actually happening."