Mechanisms of Chemical Bond Degradation in Electronic Materials

Chemical bonds in materials used for manufacturing electronic devices degrade not due to gradual wear caused by the flow of electric current, but as a result of the impact of electrons with specific energy levels.

Features of Modern Electronics

Modern electronic devices operate using semiconductor materials. The miniaturization of transistors has reached a point where even individual atomic layers become significant. For transistors and diodes to function properly, a constant flow and switching of electric current is required, which leads to heating and gradual deep-level degradation of devices, affecting the chemical bonds within the materials themselves.

The Impact of Hot Carriers

One of the factors influencing the longevity of electronics is the injection of hot carriers. In this process, electrons or holes accumulate enough energy to trigger chemical changes inside the transistor. Until recently, the exact physical mechanisms behind this phenomenon remained unknown.

Quantum Mechanism of Bond Breaking

Research has shown that degradation begins with a quantum mechanical process in which chemical bonds are broken by electrons with certain energies. It was found that the breaking of the bond between silicon and hydrogen at the silicon-oxide interface inside a transistor is not caused by the cumulative effect of many electrons, but rather by the action of a single electron that can occupy a special electronic state. This state weakens the silicon-hydrogen bond and leads to the displacement of the hydrogen atom. The energy of such a state is about seven electronvolts, which matches experimental data.

The Role of Hydrogen and Deuterium

During the production of electronics, hydrogen is intentionally added to "seal" silicon bonds that could not be closed with oxygen. If these bonds remain open, they become defects that affect the performance of electronic components. Continuous current can sometimes cause hydrogen to detach, exposing parasitic bonds. Previously, it was believed that bond breaking resulted from the accumulation of multiple electron impacts, but new data indicate the key role of a single electron.

After hydrogen detaches, its behavior follows quantum mechanical laws rather than classical ones. Unlike a classical particle, hydrogen behaves as a wave packet, and the probability of bond breaking is determined by the likelihood of this packet moving beyond a certain distance.

Studies have also shown that if deuterium (a hydrogen isotope with an extra neutron) is used instead of hydrogen, the degradation process slows down by a factor of 100 and does not depend on temperature.

Practical Significance

Based on the obtained data, a model was developed to explain these observed processes. Refining the physics of chemical bond degradation may help in developing new methods for designing and protecting electronic devices.