scholarly journals Fabricating Ultra-thin Silicon Nitride Membranes Suspended on Silicon Wafer

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Pham Thi Hong ◽  
Dang Huu Tung ◽  
Nguyen Hai Anh ◽  
Dang Tuan Linh ◽  
Nguyen Thi Thu Thao ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Silicon Wafer ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chamber System ◽  
Dual Chamber ◽  
Submicron Scale ◽  
Micron Size ◽  
Dry Etch

Ultrathin silicon nitride SiNx membrane suspended on a silicon wafer is a popular two-dimensional platform in MEMS applications. The unsupported membrane has a low thermal conductivity, is electrically insulated, and very robust against mechanical impact. Remarkably thin, it is difficult to fabricate and manipulate. Recently equipped with a dual chamber system for plasma enhanced chemical vapor deposition (PECVD) and reactive ion etching, we calibrate it to deposit silicon nitride Si3N4, silicon dioxide SiO2, and to dry etch these materials. Based on the superb quality of Si3N4, we perform a through-wafer etch that creates suspended Si3N4 membranes. The recipe is reliable and reproducible. We analyze the membrane’s chemical composition and optical properties. Although created by PECVD, the membrane is so robust that it survives multiple lithography steps. It extends our capability to study thermal transport at the submicron scale as well as to fabricate micron size devices for MEMS applicati

Improvement in Gate Dielectric Quality of Ultra Thin a: SiN:H MNS Capacitor by Hydrogen Etching of the Substrate

2002 ◽  
Vol 716 ◽  
Author(s):  
Parag C. Waghmare ◽  
Samadhan B. Patil ◽  
Rajiv O. Dusane ◽  
V.Ramgopal Rao
Keyword(s):  
Silicon Nitride ◽  
Gate Dielectric ◽  
Substrate Surface ◽  
Scaling Limit ◽  
Tunneling Current ◽  
Chemical Vapor ◽  
Poor Performance ◽  
State Density ◽  
Direct Tunneling Current

AbstractTo extend the scaling limit of thermal SiO2, in the ultra thin regime when the direct tunneling current becomes significant, members of our group embarked on a program to explore the potential of silicon nitride as an alternative gate dielectric. Silicon nitride can be deposited using several CVD methods and its properties significantly depend on the method of deposition. Although these CVD methods can give good physical properties, the electrical properties of devices made with CVD silicon nitride show very poor performance related to very poor interface, poor stability, presence of large quantity of bulk traps and high gate leakage current. We have employed the rather newly developed Hot Wire Chemical Vapor Deposition (HWCVD) technique to develop the a:SiN:H material. From the results of large number of optimization experiments we propose the atomic hydrogen of the substrate surface prior to deposition to improve the quality of gate dielectric. Our preliminary results of these efforts show a five times improvement in the fixed charges and interface state density.

Low-Temperature Formation of SiNx Gate Insulator for Thin-Film Transistor Using CAT-CVD Method

1998 ◽  
Vol 508 ◽  
Author(s):  
A. Izumi ◽  
T. Ichise ◽  
H. Matsumura
Keyword(s):  
Thin Film ◽  
Chemical Vapor Deposition ◽  
Silicon Nitride ◽  
Vapor Deposition ◽  
Thin Film Transistors ◽  
Chemical Vapor ◽  
State Density ◽  
Gate Insulator ◽  
Catalytic Chemical Vapor Deposition ◽  
Silicon Nitride Films

AbstractSilicon nitride films prepared by low temperatures are widely applicable as gate insulator films of thin film transistors of liquid crystal displays. In this work, silicon nitride films are formed around 300 °C by deposition and direct nitridation methods in a catalytic chemical vapor deposition system. The properties of the silicon nitride films are investigated. It is found that, 1) the breakdown electric field is over 9MV/cm, 2) the surface state density is about 1011cm−2eV−1 are observed in the deposition films. These result shows the usefulness of the catalytic chemical vapor deposition silicon nitride films as gate insulator material for thin film transistors.

Simple and fast fabrication of a-Si:H/c-Si hetero-junction solar cells by dual-chamber hot wire chemical vapor deposition

2014 ◽  
Vol 68 ◽  
pp. 397-402 ◽  
Author(s):  
Dae Young Jeong ◽  
Kyungmin Kim ◽  
Hee-eun Song ◽  
Jinsoo Song ◽  
Seung Jae Baik ◽  
...  
Keyword(s):  
Solar Cells ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Dual Chamber

scholarly journals Structural and Magnetic Properties of Ni81Fe19Thin Film Grown on Si(001) Substrate via Single Graphene Layer

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Gui-fang Li ◽  
Shibin Liu ◽  
Shanglin Yang ◽  
Yongqian Du
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Vapor Deposition ◽  
Graphene Layer ◽  
Structural Investigation ◽  
Annealing Temperature ◽  
Chemical Vapor ◽  
Magnetic Thin Films ◽  
Structural And Magnetic Properties

We prepared magnetic thin films Ni81Fe19on single-crystal Si(001) substrates via single graphene layer through magnetron sputtering for Ni81Fe19and chemical vapor deposition for graphene. Structural investigation showed that crystal quality of Ni81Fe19thin films was significantly improved with insertion of graphene layer compared with that directly grown on Si(001) substrate. Furthermore, saturation magnetization of Ni81Fe19/graphene/Si(001) heterostructure increased to 477 emu/cm3with annealing temperatureTa=400°C, which is much higher than values of Ni81Fe19/Si(001) heterostructures withTaranging from 200°C to 400°C.

Experimental Study of the Effect of Precursor Composition On the Microstructure of Gallium Nitride Thin Films Grown by the MOCVD Process

2021 ◽  
Author(s):  
Omar D. Jumaah ◽  
Yogesh Jaluria
Keyword(s):  
Thin Films ◽  
Gallium Nitride ◽  
Chemical Vapor Deposition ◽  
Deposition Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Transport Processes ◽  
Carrier Gas ◽  
Precursor Composition

Abstract Chemical vapor deposition (CVD) is a widely used manufacturing process for obtaining thin films of materials like silicon, silicon carbide, graphene and gallium nitride that are employed in the fabrication of electronic and optical devices. Gallium nitride (GaN) thin films are attractive materials for manufacturing optoelectronic device applications due to their wide band gap and superb optoelectronic performance. The reliability and durability of the devices depend on the quality of the thin films. The metal-organic chemical vapor deposition (MOCVD) process is a common technique used to fabricate high-quality GaN thin films. The deposition rate and uniformity of thin films are determined by the thermal transport processes and chemical reactions occurring in the reactor, and are manipulated by controlling the operating conditions and the reactor geometrical configuration. In this study, the epitaxial growth of GaN thin films on sapphire (AL2O3) substrates is carried out in two commercial MOCVD systems. This paper focuses on the composition of the precursor and the carrier gases, since earlier studies have shown the importance of precursor composition. The results show that the flow rate of trimethylgallium (TMG), which is the main ingredient in the process, has a significant effect on the deposition rate and uniformity of the films. Also the carrier gas plays an important role in deposition rate and uniformity. Thus, the use of an appropriate mixture of hydrogen and nitrogen as the carrier gas can improve the deposition rate and quality of GaN thin films.

The Cooling Rate Effect on Graphene Synthesis Using Low Pressure Chemical Vapor Deposition

2021 ◽  
Author(s):  
Byoungdo Lee ◽  
Weishen Chu ◽  
Wei Li
Keyword(s):  
Chemical Vapor Deposition ◽  
Reaction Time ◽  
Carbon Source ◽  
Cooling Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Feeding Time ◽  
Process Variables ◽  
Pressure Chemical

Abstract Low-pressure chemical vapor deposition (LPCVD) is the most efficient method to synthesize large-scale, high-quality graphene for many potential applications such as flexible electronics, solar cells, and separation membranes. The quality of LPCVD is affected by process variables including methane/hydrogen (CH4/H2) ratio, time, pressure, temperature, and cooling rate. The cooling rate has been recognized as one of the most important process variables affecting the amount of carbon source, nucleation, reaction time, and thus the quality of the LPCVD. In this research, we investigate the effect of cooling rate on the quality of graphene synthesize by changing the cooling rate and the gas feeding time. Graphene coverage is measured by Raman mapping. It is found that fast cooling rate leads to decreased carbon source reaction time, which in turn results in higher coverage by monolayer graphene. The temperature-dependent gas feeding time corresponding to different cooling rates can be used to properly supply the carbon source onto the copper surface, also leading to a higher graphene coverage.

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