Amorphous Silicon Dual Gate Thin Film Transistor & Phase Response Touch Screen Readout Scheme for Handheld Electronics Interactive AMOLED Displays

Interactive handheld electronic displays use hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) as a backplane and a Touch Screen Panel (TSP) on top as an input device. The low mobility and instability of a-Si:H TFT threshold voltage are major two issues for driving constant current as required for Active Matrix Organic Light Emitting Ddiode (AMOLED) displays. Low mobility is compensated by increasing transistor width or resorting to more expensive material TFTs. On the other hand, the ever increasing threshold voltage shift degrades the drain current under electrical operation causing OLED display to dim. Mutual capacitive TSP, the current cell phone standard, requires two layers of metals and a dielectric to be put in front of the display, further dimming the device and adding to visual noise due to sun reflection, not to mention increased integration cost and decreased yield. This thesis focuses on the aforementioned technological hurdles of a handheld electronic display by proposing a dual-gate TFT used as an OLED current driving TFT and a novel phase response readout scheme that can be applied to a one metal track TSP. Our dual-gate TFT has shown on average 20% increase in drive current over a single gate TFT fabricated in the same batch, attributed to the aid of a top channel to the convention bottom channel TFT. Furthermore the dual gate TFT shows three times the Poole-Frenkel current than the single gate TFT attributed to the increase in gate to drain overlap. The dual-gate TFT shows a 50% improvement in threshold voltage shift over a single gate TFT at room temperature, but only ~8% improvement under 75ºC. This is an important observation as it shows an accelerated threshold voltage shift in the dual-gate. This difference in the rate of threshold voltage change under varying temperature is attributed to the difference in interface states, supporting Libsch and Kanicki’s multi-level temperature dependant dielectric trapping model. The phase response TSP readout scheme requires IC only on one side of the display. Cadence Spectre simulation results showed that both touch occurrence and touch position can be obtained using only one metal layer

Amorphous Silicon Dual Gate Thin Film Transistor & Phase Response Touch Screen Readout Scheme for Handheld Electronics Interactive AMOLED Displays

Interactive handheld electronic displays use hydrogenated amorphous silicon (a-Si:H) thin film transistor (TFT) as a backplane and a Touch Screen Panel (TSP) on top as an input device. The low mobility and instability of a-Si:H TFT threshold voltage are major two issues for driving constant current as required for Active Matrix Organic Light Emitting Ddiode (AMOLED) displays. Low mobility is compensated by increasing transistor width or resorting to more expensive material TFTs. On the other hand, the ever increasing threshold voltage shift degrades the drain current under electrical operation causing OLED display to dim. Mutual capacitive TSP, the current cell phone standard, requires two layers of metals and a dielectric to be put in front of the display, further dimming the device and adding to visual noise due to sun reflection, not to mention increased integration cost and decreased yield. This thesis focuses on the aforementioned technological hurdles of a handheld electronic display by proposing a dual-gate TFT used as an OLED current driving TFT and a novel phase response readout scheme that can be applied to a one metal track TSP. Our dual-gate TFT has shown on average 20% increase in drive current over a single gate TFT fabricated in the same batch, attributed to the aid of a top channel to the convention bottom channel TFT. Furthermore the dual gate TFT shows three times the Poole-Frenkel current than the single gate TFT attributed to the increase in gate to drain overlap. The dual-gate TFT shows a 50% improvement in threshold voltage shift over a single gate TFT at room temperature, but only ~8% improvement under 75ºC. This is an important observation as it shows an accelerated threshold voltage shift in the dual-gate. This difference in the rate of threshold voltage change under varying temperature is attributed to the difference in interface states, supporting Libsch and Kanicki’s multi-level temperature dependant dielectric trapping model. The phase response TSP readout scheme requires IC only on one side of the display. Cadence Spectre simulation results showed that both touch occurrence and touch position can be obtained using only one metal layer

The CMS experiment at the CERN LHC

The Compact Muon Solenoid (CMS) detector is described. The detector operates at the Large Hadron Collider (LHC) at CERN. It was conceived to study proton-proton (and leadlead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 1034 cm-2s-1 (1027 cm-2s-1). At the core of the CMS detector sits a high-magnetic field and large-bore superconducting solenoid surrounding an all-silicon pixel and strip tracker, a lead-tungstate scintillating-crystals electromagnetic calorimeter, and a brass-scintillator sampling hadron calorimeter. The iron yoke of the flux-return is instrumented with four stations of muon detectors covering most of the 4π solid angle. Forward sampling calorimeters extend the pseudorapidity coverage to high values (|η| ≤ 5) assuring very good hermeticity. The overall dimensions of the CMS detector are a length of 21.6 m, a diameter of 14.6 m and a total weight of 12500 t

NASA Tech Briefs, January 1996

This issue has a special focus on sensors, and include articles on Electronic Components and Circuits, Electronic Systems, Physical Sciences, Materials, Computer Programs, Mechanics, Machinery/Automation, Manufacturing/Fabrication, and Mathematics and Information Science

The CMS experiment at the CERN LHC

The Compact Muon Solenoid (CMS) detector is described. The detector operates at the Large Hadron Collider (LHC) at CERN. It was conceived to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 10^(34) cm^(−2) s^(−1) (10^(27) cm^(−2) s^(−1)). At the core of the CMS detector sits a high-magnetic-field and large-bore superconducting solenoid surrounding an all-silicon pixel and strip tracker, a lead-tungstate scintillating-crystals electromagnetic calorimeter, and a brass-scintillator sampling hadron calorimeter. The iron yoke of the flux-return is instrumented with four stations of muon detectors covering most of the 4π solid angle. Forward sampling calorimeters extend the pseudorapidity coverage to high values (|η| ≤ 5) assuring very good hermeticity. The overall dimensions of the CMS detector are a length of 21.6 m, a diameter of 14.6 m and a total weight of 12500 t

The CMS experiment at the CERN LHC

The Compact Muon Solenoid (CMS) detector is described. The detector operates at the Large Hadron Collider (LHC) at CERN. It was conceived to study proton-proton (and lead-lead) collisions at a centre-of-mass energy of 14 TeV (5.5 TeV nucleon-nucleon) and at luminosities up to 10^(34) cm^(−2) s^(−1) (10^(27) cm^(−2) s^(−1)). At the core of the CMS detector sits a high-magnetic-field and large-bore superconducting solenoid surrounding an all-silicon pixel and strip tracker, a lead-tungstate scintillating-crystals electromagnetic calorimeter, and a brass-scintillator sampling hadron calorimeter. The iron yoke of the flux-return is instrumented with four stations of muon detectors covering most of the 4π solid angle. Forward sampling calorimeters extend the pseudorapidity coverage to high values (|η| ≤ 5) assuring very good hermeticity. The overall dimensions of the CMS detector are a length of 21.6 m, a diameter of 14.6 m and a total weight of 12500 t

NASA Tech Briefs, September 1993

Topics include: Microelectronics; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Life Sciences; Books and Reports