Dislocation-induced noise in semiconductors

Rapid advances in the semiconductor technology of nano-scale integration, optoelectronics for communication needs, and micromachines make the susceptibility of semiconductor systems to electronic noise a crucial issue. Electronic systems designed to carry high switching speed, large gain, and large power could be compromised by internally generated noise. Defects (especially extended) in crystalline structure are known to be sites of intense scattering and trapping in flows of carriers, and therefore are recognized as strong generators of noise in electronic materials and devices. Our study was focused on 1/f noise generated by dislocations. Even an extremely low level of this noise is rather disturbing to the operation of many electronic and optoelectronic devices. In the current study a new noise figure of merit was introduced and applied in analysing the potential use of such materials as Si, Si-Ge, SiC, GaAs, GaN, and AlN. The potential low-noise performance of electronic materials is connected to the presence of extended crystalline defects, dislocations. A model was developed which links the magnitude of the recombination rate at the dislocation with fluctuation of the current, which could be measured by electron-beam-induced-current techniques. This model considers the dynamic change of the dislocation potential for a defect positioned inside an active area of a device, when the external bias changes at a p-n junction, at the gate of a field-effect-transistor or at the cavity of a laser.