A highly sensitive vertical plug-in source drain high Schottky barrier bilateral gate controlled bidirectional tunnel field effect transistor.

In this article, we propose a highly sensitive vertically plug-in source drain contacts high Schottky barrier based bilateral gate and assistant gate controlled bidirectional tunnel field Effect transistor (VPISDC-HSB-BTFET). It can achieve much more sensitive forward current driving ability than the previously proposed High Schottky barrier source/drain contacts based bilateral gate and assistant Gate controlled bidirectional tunnel field Effect transistor (HSB-BTFET). Silicon body of the proposed VPISDC-HSB-BTFET is etched into a U-shaped structure. By etching both sides of the silicon body to form vertically plug-in source drain contacts, the source and drain electrodes are plugged into a certain height of the vertical parts of both sides of the U-shaped silicon body. Thereafter, the efficient area of the band-to-band tunneling generation region near the source drain contacts is significantly increased, so as to achieve sensitive ON-state current driving ability. Comparing to the mainstream FinFET technology, lower subthreshold swing, lower static power consumption and Higher Ion-Ioff ratio can be achieved.

Characterization and Modeling of a Pt-In2O3 Resistive Sensor for Hydrogen Detection at Room Temperature.

Sensitive H2 sensors at low concentrations and room temperature are desired for the early warning and control of hydrogen leakage. In this paper, a resistive sensor based on Pt-doped In2O3 nanoparticles was fabricated using inkjet printing process. The H2 sensing performance of the sensor was evaluated at low concentrations below 1% at room temperature. It exhibited a relative high response of 42.34% to 0.6% H2. As the relative humidity of 0.5% H2 decreased from 34% to 23%, the response decreased slightly from 34% to 23%. The sensing principle and the humidity effect were discussed. A dynamic current sensing model for dry H2 detection was proposed based on Wolkenstein theory and experimentally verified to be able to predict the sensing behavior of the sensor. The H2 concentration can be calculated within a short measurement time using the model without waiting for the saturation of the response, which significantly reduces the sensing and recovery time of the sensor. The sensor is expected to be a promising candidate for room-temperature H2 detection, and the proposed model could be very helpful in promoting the application of the sensor for real-time H2 leakage monitoring.

A Study on the Effect of the Structural Parameters and Internal Mechanism of a Bilateral Gate-Controlled S/D Symmetric and Interchangeable Bidirectional Tunnel Field Effect Transistor.

A bilateral gate-controlled S/D symmetric and interchangeable bidirectional tunnel field effect transistor (B-TFET) is proposed in this paper, which shows the advantage of bidirectional switching characteristics and compatibility with CMOS integrated circuits compared to the conventional asymmetrical TFET. The effects of the structural parameters, e.g., the doping concentrations of the N+ region and P+ region, length of the N+ region and length of the intrinsic region, on the device performances, e.g., the transfer characteristics, Ion-Ioff ratio and subthreshold swing, and the internal mechanism are discussed and explained in detail.

A Highly Sensitive FET-Type Humidity Sensor with Inkjet-Printed Pt-In2O3 Nanoparticles at Room Temperature.

In this work, Pt-doped In2O3 nanoparticles (Pt-In2O3) were inkjet printed on a FET-type sensor platform that has a floating gate horizontally aligned with a control gate for humidity detection at room temperature. The relative humidity (RH)-sensing behavior of the FET-type sensor was investigated in a range from 3.3 (dry air in the work) to about 18%. A pulsed measurement method was applied to the transient RH-sensing tests of the FET-type sensor to suppress sensor baseline drift. An inkjet-printed Pt-In2O3 resistive-type sensor was also fabricated on the same wafer for comparison, and it showed no response to low RH levels (below 18%). In contrast, the FET-type sensor presented excellent low humidity sensitivity and fast response (32% of response and 58 s of response time for 18% RH) as it is able to detect the work-function changes of the sensing material induced by the physisorption of water molecules. The sensing mechanism of the FET-type sensor and the principle behind the difference in sensing performance between two types of sensors were explained through the analysis on the adsorption processes of water molecules and energy band diagrams. This research is very useful for the in-depth study of the humidity-sensing behaviors of Pt-In2O3, and the proposed FET-type humidity sensor could be a potential candidate in the field of real-time gas detection.

Humidity-Sensitive Field Effect Transistor with In2O3 Nanoparticles as a Sensing Layer.

In this work, we investigate the humidity-sensing performance on a humidity-sensitive p-channel field effect transistor (FET) having a floating-gate (FG) and a control-gate (CG) placing horizontally each other. A sensing layer is formed onto a part of the CG and the O/N/O stack over the FG by inkjet-printing process. The printed ink is composed of indium oxide (In2O3. nanoparticles and dimethylformamide (HCON(CH3)2) as solvent. DC/Pulsed measurements are carried out by switching chamber ambience between dry and humid N2 at 25 °C. Pulsed measurement effectively alleviates the ID drift of the device. When the device is exposed to humidity, the |ID| is appreciably decreased in the p-channel FET-type sensor, since H2O molecules act as an electron donor. The sensitivity of the sensor increases with increasing relative humidity up to about 68% and decreases with further increasing relative humidity.

Observation of physisorption in a high-performance FET-type oxygen gas sensor operating at room temperature.

Oxygen (O2) sensors are needed for monitoring environment and human health. O2 sensing at low temperature is required, but studies are lacking. Here we report, for the first time, that the performance of a field effect transistor (FET)-type O2 sensor operating at 25 °C was improved greatly by a physisorption sensing mechanism. The sensing material was platinum-doped indium oxide (Pt-In2O3) nanoparticles formed by an inkjet printer. The FET-type sensor showed excellent repeatability under a physisorption mechanism and showed much better sensing performance than a resistor-type sensor fabricated on the same wafer at 25 °C. The sensitivity of the sensor increased with increasing Pt concentration up to ∼10% and decreased with further increasing Pt concentration. When the sensing temperature reached 140 °C, the sensing mechanism of the sensor changed from physisorption to chemisorption. Interestingly, the pulse pre-bias before the read bias affected chemisorption but had no effect on physisorption.