The Noise Research group headed by professor Bosman [NEB 565, 352-392-0910, firstname.lastname@example.org] has the capability to carry out computer controlled low frequency electrical noise measurements as a function of bias and ambient temperature between 1 Hz and 100 KHz. As a rule carrier trapping in defects results in Lorentzian shaped current noise components dominating the low frequency device noise spectrum in this range. Noise measurements carried out as a function of temperature present a sensitive tool to measure defect energies in devices as made that actually affect the charge transport process via carrier trapping. Changes in noise levels before and after applying stress will be correlated with stress or hot carrier induced defect formation. Specifically for FET structures, the lateral position of the dominant carrier trapping defects can be determined from the drain bias dependence of the measured trapping noise spectra, whereas the gate bias dependence of the noise will reveal the microscopic distance of the trapping defect centers into the barrier layer measured from the channel. The noise magnitude correlates with the number of defects. Consequently, reverse engineering of the noise data will result in a detailed map of induced defect centers and energies responsible for trapping carriers and thus affecting device performance and degradation . This map will be a powerful instrument for increasing device reliability via device geometry and material choice optimization.
Reference: 1. F.-C. Hou, G. Bosman, and M. E. Law, “Simulation of oxide trapping noise in sub-micron n-MOSFETs,” IEEE Trans. Electron Devices, vol. 50, pp. 846-852, 2003.
Staff on this Research
- Hemant Rao, NEB 585,352-392-4900, email@example.com
- Student 2, to be appointed
Research Goal Statement
We hope to be able to model the location, densities, and activation energies of hot electron or reverse piezo electrically generated defects that negatively affect the reliability of GaN devices using low frequency noise measurements and the FLOOPS/FLOODS numerical sofware suite expanded with noise simulation capability.
Hemant Rao and Gijs Bosman, “Study of RF reliability of GaN HEMTs using low frequency noise spectroscopy,” IEEE Trans. Device Mater. Rel., Vol. 12, pp. 31-36, 2012. Visit journal
Hemant Rao and Gijs Bosman, “Device reliability study of high gate electric field effects in AlGaN/GaN high electron mobility transistors using low frequency noise spectroscopy,” J. Appl. Phys., Vol. 108, pp. 053707-1 - 053707-5, 7 September 2010. Paper in PDF Visit journal
Hemant Rao and Gijs Bosman, “Simultaneous low-frequency noise characterization of gate and drain currents in AlGaN/GaN high electron mobility transistors,” J. Appl. Phys., Vol. 106, pp. 103712-1 - 103712-5, 20 November 2009. Paper in PDF Visit journal
Hemant Rao and Gijs Bosman, “Device reliability study of GaN HEMTs using both low frequency noise and microwave noise temperature spectroscopy,” in 2011 21st International Conference on Noise and Fluctuations (ICNF), Toronto, Canada, Jun 12-16, 2011, pp. 464-467. Paper in PDF Slides in PDF Visit journal
Hemant Rao and Gijs Bosman, “Device reliability study of AlGaN/GaN high electron mobility transistors under high gate and channel electric fields via low frequency noise spectroscopy,” Microelectronics Reliability, Vol. 50, p. 1528-1531, 2010 (21st ESREF, Gaeta, Italy, Oct 11-15, 2010). Paper in PDF Slides in PDF Visit journal