Semiconductor biosensors

1987 ◽  
Vol 316 (1176) ◽  
pp. 47-60 ◽  
Keyword(s):  
Immobilized Enzymes ◽  
Oxide Semiconductor ◽  
Gas Sensitivity ◽  
Metal Gates ◽  
Mos Devices ◽  
Steady State Responses ◽  
Catalytic Metal ◽  
Mos Structures ◽  
State Responses

Hydrogen- and ammonia-sensitive metal-oxide semiconductor (MOS) structures are described. Special attention is paid to ammonia-sensitive MOS devices with thin ( ca . 3 nm) iridium or platinum gates. It is shown how these devices can be used in combination with immobilized enzymes to develop bioprobes or biosensing systems. The temperature dependence of the gas sensitivity of MOS structures with catalytic metal gates is considered. It is demonstrated that at low temperatures (30-40 °C) iridium gates have a faster response to ammonia than platinum gates, and that Ir-Mos structures thus are better suited for the development of biosensors. It is also shown that at high temperatures (190-200 °C) platinum gates can be used to detect unsaturated hydrocarbons such as ethylene. Gas evolution from ripening fruits was monitored with such a sensor. Some biosensing applications of ammonia sensitive Ir-gate MOS devices are described; for example, the determination of urea and creatinine. The devices are used both to measure a pulse of ammonia in a flowthrough system and to measure in situ steady-state responses as a bioprobe. The special features of gas sensors used for biosensing purposes are summarized.

scholarly journals A Model for Neutron Radiation Damage in Metal Oxide Semiconductor (MOS) Structures

2016 ◽  
Vol 706 ◽  
pp. 51-54
Author(s):  
Haider F. Abdul Amir ◽  
Abu Hassan Husin ◽  
Saafie Salleh ◽  
Fuei Pien Chee
Keyword(s):  
Lattice Structure ◽  
Neutron Radiation ◽  
Mean Free Path ◽  
Depletion Region ◽  
Oxide Semiconductor ◽  
Mos Devices ◽  
Single Neutron ◽  
Electron Hole Pair ◽  
Mos Structures

Neutron bombardment on semiconductor material causes defects, one such primary physical effect is the formation of displacement defects within the crystal lattice structure, and such defects effectively decrease the mean free path and thus shorten the recombination time. Ionizing radiation causes creation of electron-hole pair in the gate oxide and in parasitic insulating layers of the MOS devices. Calculations show increase of the dark current in depletion region caused by a single neutron. Determination of energy and angular distribution of primary knock on atoms, with 14 MeV neutron irradiation in silicon are presented.

Characterization of Diverse Gate Oxides on 4H-SiC 3D Trench-MOS Structures

2013 ◽  
Vol 740-742 ◽  
pp. 691-694 ◽  
Author(s):  
Christian T. Banzhaf ◽  
Michael Grieb ◽  
Achim Trautmann ◽  
Anton J. Bauer ◽  
Lothar Frey
Keyword(s):  
Silicon Dioxide ◽  
Dielectric Breakdown ◽  
Interface State ◽  
Oxide Semiconductor ◽  
Breakdown Field ◽  
Flat Band ◽  
Mos Devices ◽  
State Densities ◽  
Mos Structures

This study focuses on the characterization of silicon dioxide (SiO2) layers, either thermally grown or deposited on trenched 100 mm 4H-silicon carbide (SiC) wafers. We evaluate the electrical properties of silicon dioxide as a gate oxide (GOX) for 3D metal oxide semiconductor (MOS) devices, such as Trench-MOSFETs. Interface state densities (DIT) of 1*1011cm-2eV-1under flat band conditions were determined using the hi-lo CV-method [1]. Furthermore, current-electric field strength (IE) measurements have been performed and are discussed. Trench-MOS structures exhibited dielectric breakdown field strengths up to 10 MV/cm.

Fixed-charge generation in SiO2/GaN MOS structures by forming gas annealing and its suppression by controlling Ga-oxide interlayer growth

2021 ◽  
Author(s):  
Hidetoshi Mizobata ◽  
Mikito Nozaki ◽  
Takuma Kobayashi ◽  
Takuji Hosoi ◽  
Takayoshi Shimura ◽  
...  
Keyword(s):  
Defect Formation ◽  
Fixed Charge ◽  
Oxide Semiconductor ◽  
Oxide Growth ◽  
Charge Generation ◽  
Mos Devices ◽  
Defect Passivation ◽  
Interface Structures ◽  
Electrical Characterizations ◽  
Mos Structures

Abstract A recent study has shown that anomalous positive fixed charge is generated at SiO2/GaN interfaces by forming gas annealing (FGA). Here, we conducted systematic physical and electrical characterizations of GaN-based metal-oxide-semiconductor (MOS) structures to gain insight into the charge generation mechanism and to design optimal interface structures. A distinct correlation between the amount of FGA-induced fixed charge and interface oxide growth indicated the physical origins of the fixed charge to be defect formation driven by reduction of the Ga-oxide (GaOx) interlayer. This finding implies that, although post-deposition annealing in oxygen compensates for oxygen deficiencies and FGA passivates defect in GaN MOS structures, excessive interlayer GaOx growth leads to instability in the subsequent FGA treatment. On the basis of this knowledge, SiO2/GaOx/GaN MOS devices with improved electrical properties were fabricated by precisely controlling the interfacial oxide growth while taking advantage of defect passivation with FGA.

Effect of Phosphorus Implantation Prior to Oxidation on Electrical Properties of Thermally Grown SiO2/4H-SiC MOS Structures

2014 ◽  
Vol 806 ◽  
pp. 133-138 ◽  
Author(s):  
Aleksey Mikhaylov ◽  
Tomasz Sledziewski ◽  
Alexey Afanasyev ◽  
Victor Luchinin ◽  
Sergey A. Reshanov ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Reference Sample ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Phosphorus Concentration ◽  
Interface Traps ◽  
Mos Capacitor ◽  
Mos Devices ◽  
Dry Oxidation ◽  
Mos Structures

The electrical properties of metal-oxide-semiconductor (MOS) devices fabricated using dry oxidation on phosphorus-implanted n-type 4H-SiC (0001) epilayers have been investigated. MOS structures were compared in terms of interface traps and reliability with reference sample which was produced by dry oxidation under the same conditions. The notably lower interface traps density measured in MOS capacitor with phosphorus concentration exceeding 1018 cm-3 at the SiO2/SiC interface was attributed to interface traps passivation by incorporated phosphorus ions.

A COMPREHENSIVE SIMULATOR OF THE HUMAN PULMONARY SYSTEM: VALIDATION WITH DETERMINATION OF TOTALCO2AND DIAGNOSIS OF ACID-BASE ABNORMALITIES

2009 ◽  
Vol 17 (01) ◽  
pp. 153-171
Author(s):  
MOHAMMAD REZA BIGDELI ◽  
SOHRAB HAJIZADEH ◽  
BEHZAD BANIEGHBAL ◽  
MOHAMMAD REZA MASJDI
Keyword(s):  
Mathematical Model ◽  
Physicochemical Properties ◽  
Comprehensive Model ◽  
Acid Base ◽  
System Validation ◽  
Steady State Responses ◽  
Fluid Compartments ◽  
The Mathematical Model ◽  
State Responses

In previous models, heart-lung-blood interactions and their physicochemical properties have not been considered in comprehensive simulators and an integrated mathematical model has not been presented. The aim of the present study is to combine different phenomena involved in the cardiopulmonary function, which are often considered separately. In this study, the variables that constitute a comprehensive model; which includes physicochemical reactions of O2and CO2in the blood and fluid compartments, V/Q, pH , body temperature and diffusion limitation in the adult human and its ability to provide realistic response under different physiological and pathophysiological conditions; have been evaluated. The new biological system model consists of two subsystems: physicochemical properties of blood and physiological subsystem models. Based on the mentioned parameters, comprehensive simulator model has been suggested as following: [Formula: see text] According to the literature, all patients [COPD (20) and asthma (20)] showed acid-base imbalances. The mathematical model has been validated by diagnosis of acid-base abnormalities via calculating the total CO2and T40HCO3in physiological and pathophysiological conditions, and then the results compared to literature experimental data. Our comprehensive model provides results consistent with dynamic and steady state responses measured in subjects undergoing physiological and pathophysiological conditions. This might enable us to deepen our understanding of the cardiopulmonary system as a whole.

Estimating the Audiogram Using Multiple Auditory Steady-State Responses

2002 ◽  
Vol 13 (04) ◽  
pp. 205-224 ◽  
Author(s):  
Andrew Dimitrijevic ◽  
Sasha M. John ◽  
Patricia Van Roon ◽  
David W. Purcell ◽  
Julija Adamonis ◽  
...  
Keyword(s):  
Steady State ◽  
Correlation Coefficients ◽  
Behavioral Threshold ◽  
Behavioral Thresholds ◽  
Sensorineural Hearing Impairment ◽  
Steady State Responses ◽  
Auditory Steady State Responses ◽  
Tonal Stimuli ◽  
Conductive Hearing ◽  
State Responses

Multiple auditory steady-state responses were evoked by eight tonal stimuli (four per ear), with each stimulus simultaneously modulated in both amplitude and frequency. The modulation frequencies varied from 80 to 95 Hz and the carrier frequencies were 500, 1000, 2000, and 4000 Hz. For air conduction, the differences between physiologic thresholds for these mixed-modulation (MM) stimuli and behavioral thresholds for pure tones in 31 adult subjects with a sensorineural hearing impairment and 14 adult subjects with normal hearing were 14 ± 11, 5 ± 9, 5 ± 9, and 9 ± 10 dB (correlation coefficients .85, .94, .95, and .95) for the 500-, 1000-, 2000-, and 4000-Hz carrier frequencies, respectively. Similar results were obtained in subjects with simulated conductive hearing losses. Responses to stimuli presented through a forehead bone conductor showed physiologic-behavioral threshold differences of 22 ± 8, 14 ± 5, 5 ± 8, and 5 ± 10 dB for the 500-, 1000-, 2000-, and 4000-Hz carrier frequencies, respectively. These responses were attenuated by white noise presented concurrently through the bone conductor.

scholarly journals Atomic Layer Deposition (ALD) of Metal Gates for CMOS

2019 ◽  
Vol 9 (11) ◽  
pp. 2388 ◽  
Author(s):  
Chao Zhao ◽  
Jinjuan Xiang
Keyword(s):  
Atomic Layer Deposition ◽  
Field Effect Transistors ◽  
Material Selection ◽  
Atomic Layer ◽  
Oxide Semiconductor ◽  
Metal Gate ◽  
Gate Stack ◽  
Short Channel ◽  
Metal Gates ◽  
Layer Deposition

The continuous down-scaling of complementary metal oxide semiconductor (CMOS) field effect transistors (FETs) had been suffering two fateful technical issues, one relative to the thinning of gate dielectric and the other to the aggressive shortening of channel in last 20 years. To solve the first issue, the high-κ dielectric and metal gate technology had been induced to replace the conventional gate stack of silicon dioxide layer and poly-silicon. To suppress the short channel effects, device architecture had changed from planar bulk Si device to fully depleted silicon on insulator (FDSOI) and FinFETs, and will transit to gate all-around FETs (GAA-FETs). Different from the planar devices, the FinFETs and GAA-FETs have a 3D channel. The conventional high-κ/metal gate process using sputtering faces conformality difficulty, and all atomic layer deposition (ALD) of gate stack become necessary. This review covers both scientific and technological parts related to the ALD of metal gates including the concept of effect work function, the material selection, the precursors for the deposition, the threshold voltage (Vt) tuning of the metal gate in contact with HfO2/SiO2/Si. The ALD of n-type metal gate will be detailed systematically, based mainly on the authors’ works in last five years, and the all ALD gate stacks will be proposed for the future generations based on the learning.

Sign in / Sign up

Export Citation Format

Share Document