Researchers can now observe transistors in chips in operation
Researchers at the University of Adelaide have developed a new method with which the activity of transistors within a chip can be observed during ongoing operation. The technology also entails some risks.
Most accurate measurements with terahertz radiation
The core of the technology is a so-called vector network analyzer (VNA), a laboratory device that generates microwave signals with a precisely defined frequency and phase. These signals are converted into terahertz waves via a frequency converter and directed specifically at an active microchip.
As the chip works and its transistors are constantly switched on and off, the reflected signal changes minimally. These subtle differences are then detected, converted back into microwaves and compared with the original signal IEEE Spectrum reported. In order to make these extremely small deviations measurable, the researchers had to adapt their devices. In particular, a homodyne quadrature detector was used, which is the only instrument capable of reliably detecting tiny differences in amplitude and phase. Without this technology, disturbances, such as noise in the measuring system, would mask the signals.
The method offers the ability to look directly into the interior of a processor while it is working. Previous methods usually only allowed indirect or static analyses. The new technology therefore opens up completely new possibilities for the diagnosis, development and quality assurance of chips.
Technology poses security problems
However, the technology still faces challenges. In complex processors with multiple layers on top of each other, i.e. in modern 3D chip designs, it is difficult to determine which layer a signal comes from. If overlying layers shield the radiation, the measurement becomes inaccurate. The scientists are therefore working on further improving the sensitivity of the measuring devices.
Security issues are also coming into focus. In the future, attackers could use the technology to read data from processors during ongoing operation. Since information must be decrypted before processing, conventional encryption methods do not offer any protection here. Appropriate countermeasures are therefore likely to soon become an important issue for the IT security industry.
