Simulation study on influence of interface trap position in Sii-xGex Gate-All-Around (GAA) field-effect transistor
In this paper, performance degradation of Si1−xGex gate-all-around (GAA) Field-Effect Transistor (FET) depending on interface trap position was investigated through TCAD simulations. Interface traps were located at three different points along the channel. Parameters such as hole mobility and energy band were analyzed to understand the effects of partially generated interface traps by unstable GeOx.
Preferential oxidation of Si in SiGe for shaping Ge-rich SiGe gate stacks
The oxidation of SiGe is quite different from that of Si or Ge. By paying attention to the oxidation kinetics of SiGe, a gate stack formation guideline on SiGe is proposed. Based on the understanding of oxidation kinetics, we design the gate stack formation process and demonstrate very good C-V characteristics on SiGe with Si-cap free passivation, by direct deposition of a designed dielectric film, followed by an optimal post-deposition annealing.
rPET detectors design and data processing
Small animal PET systems based on rotating planar detectors posses some interesting advantages for high sensitivity, high resolution imaging. We have designed the rPET detectors based on MLS crystals assembled on a 30times30 matrix optically coupled to a flat-panel PS-PMT. Weighted position readout circuits pre-process the 64 signals from the 8times8 anodes matrix, which are digitized using a charge-integrating converter. The amplification electronics, including the trigger output for coincidence detection, and the high voltage supply are integrated in a three PCBs stack that forms the base attached to the back of the PMT. The whole assembly is enclosed in a light tight, lead (Pb) shielded aluminum box. The detectors are mounted on a rotating gantry with more than 180 degrees rotation span. The digitized events are screened and histogramed, and a modified center of gravity algorithm removes from the position calculation those signals with poor signal to noise ratio. Apparent mean crystal size on the 511 keV field-flood images is 0.6 mm, mean peak-to-valley ratio is better than 8, and intrinsic resolution is 1.5 mm at the central row, with the energy window wide open. Sensitivity (CPS) for a pair of these detectors set in coincidence at 160 mm distance is 1%