Papers by Keyword: Charge Collection

Abstract: Single event transient of a PMOS using strained Silicon-Germanium in a sub-100nm bulk process is studied by 3D TCAD simulation. The impact of bias voltage, temperature, LET, and struck position on SET is considered. Our simulation results demonstrate that bias voltage in the range 0.8 to 1.2V greatly influence the amplitude of SET current. Temperature has a stronger influence on a SiGe channel PMOS than a Si-channel PMOS. Both SET current duration and total collection charge increase as LET increases, and SET current duration and total collection of a SiGe channel PMOS are larger than that of Si channel PMOS. These simulation results are beneficial to the space application of SiGe circuits.

Abstract: A model of combining of guard rings and buried n⁺ layer in mitigating charge collection and charge sharing is presented in this paper. 3-D TCAD simulation results indicate that for 90-nm CMOS process, PMOS charge collection and charge sharing can be mitigated more effectively with the combination model than the solely use of guard rings or buried n⁺ layer. With the combination, a noticeable improvement on angled ion strikes is also represented. The model shows a significant advantage in high-energy ion strikes and angled ion strikes.

Abstract: Defects in electron-irradiated 6H-SiC diodes have been studied by single alpha particle induced charge transient spectroscopy and deep level transient spectroscopy (DLTS) in order to identify critical defects responsible for the charge collection efficiency (CCE) decreased by high-energy electron irradiation. The defect X2 detected by the charge transient spectroscopy and the electron trap Ei detected by the DLTS had a similar activation energy of around 0.50 eV. In addition, the annealing at 200oC completely removed defects X2 and Ei, and restored the CCE. The defect X2 is attributed to the electron trap Ei, and responsible for the decreased CCE.

Abstract: The charge generated in 6H-SiC n+p diodes by oxygen (O) ion irradiation at energies between 6 and 15 MeV was evaluated using the Transient Ion Beam Induced Current (TIBIC). The signal peak of the transient current increases, and the fall-time decreases with increasing applied reverse bias. The value of collected charge increases with increasing applied reverse bias, and the saturation of the collected charge was observed in high reverse bias regions (e.g. above 70 V in the case of 12MeV O-irradiation). The charge generated in the deeper region than the depletion layer is collected due to the "funneling effect". Almost all charge generated in n+p SiC diodes by O-irradiation between 6 and 15 MeV is collected when the length of the depletion layer becomes longer than the projection range of ions.

Abstract: The spectrometric characteristics of the detectors based on 4H-SiC using 4.8-7.7 MeV a-particles were determined. The Cr Schottky barriers with areas of 1×10-2 cm2 were performed^by vacuum thermal evaporation on 4H-SiC epitaxial layers grown by chemical vapor deposition (CVD) with thickness 26 and 50 µm. The concentrations of the uncompensated donors into CVD epitaxial layers were (6-10) ×1014 cm-3, that allowed to develop a detector depletion region up to 30 µm using reverse bias of 400 V. The energy resolution less than 20 keV (0.34%) for lines of 5.0- 5.5 MeV was achieved that is twice as large of the resolution of high-precision Si-based detectors prepared on specialized technology. The maximum signal amplitude of 4H-SiC - detectors corresponding to the average electron-hole pair generation energy was found to be 7.70 eV.