Query: Ultralow-dielectric-constant amorphous boron nitride

Candidate papers:

abstract: Decrease in processing speed due to increased resistance and capacitance delay is a major obstacle for the down scaling of electronics 1 3 Minimizing the dimensions of interconnects (metal wires that connect different electronic components on a chip) is crucial for the miniaturization of devices. Interconnects are isolated from each other by non conducting (dielectric) layers. So far, research has mostly focused on decreasing the resistance of scaled interconnects because integration of dielectrics using low temperature deposition processes compatible with complementary metal oxide semiconductors is technically challenging. Interconnect isolation materials must have low relative dielectric constants k values) serve as diffusion barriers against the migration of metal into semiconductors, and be thermally, chemically and mechanically stable. Specifically, the International Roadmap for Devices and Systems recommends 4 the development of dielectrics with k values of less than 2 by 2028. Existing low k materials (such as silicon oxide derivatives, organic compounds and aerogels) have k values greater than 2 and poor thermo mechanical properties 5 Here we report three nanometre thick amorphous boron nitride films with ultralow k values of 1.78 and 1.16 (close to that of air, k 1) at operation frequencies of 100 kilohertz and 1 megahertz, respectively. The films are mechanically and electrically robust, with a breakdown strength of 7.3 megavolts per centimetre, which exceeds requirements. Cross sectional imaging reveals that amorphous boron nitride prevents the diffusion of cobalt atoms into silicon under very harsh conditions, in contrast to reference barriers. Our results demonstrate that amorphous boron nitride has excellent low k dielectric characteristics for high performance electronics. Thin films of amorphous boron nitride are mechanically and electrically robust, prevent diffusion of metal atoms into semiconductors and have ultralow dielectric constants that exceed current recommendations for high performance electronics.
author_names: Seokmo Hong

Chang-Seok Lee

Min-Hyun Lee

Yeongdong Lee

Kyung Yeol Ma

Gwangwoo Kim

Seong In Yoon

Kyuwook Ihm

Ki-Jeong Kim

Tae Joo Shin

Sang Won Kim

Eun-chae Jeon

Hansol Jeon

Ju-Young Kim

Hyung-Ik Lee

Zonghoon Lee

Aleandro Antidormi

Stephan Roche

Manish Chhowalla

Hyeon-Jin Shin

Hyeon Suk Shin
title: Ultralow dielectric constant amorphous boron nitride
venue: Nature
year: 2020

abstract: Abstract Good insulating amorphous boron nitride films are grown on Si substrates by radio frequency sputtering method using hexagonal boron nitride target at room temperature. Film thickness by surface profilometer, elemental composition by X ray photoelectron spectroscopy, chemical bonding by Raman spectroscopy and morphologies by scanning electron microscopy, have been studied. The grown films are of sp2 bonded BN and verified the assumption that growth rate varies as the growth mode transition occurs. Electrical properties are elaborated via current voltage characteristics and capacitance voltage profiling has been studied based on metal insulator semiconductor (MIS) structure. Breakdown failure was evaluated to be greater than 10 MV/cm while dielectric constant was more than 3 for grown films. This exploration will support to synthesize BN at low temperature and expand its usage in electronics.
author_names: Qasim Abbas

Hongwei Liang

Jianjun Shi

Yuanpeng Chen

Xiaochuan Xia

Aqrab ul Ahmad

Jianxun Liu

Guotong Du
title: Growth and characterization of amorphous boron nitride dielectric films on Si via RF sputtering at room temperature
year: 2018

abstract: As a structural analogue of graphene, boron nitride nanosheets (BNNSs) have attracted ever growing research interest in the past few years, due to their remarkably mechanical, electrical, and thermal properties. The preparation of BNNS aerogels is considered to be one of the most effective approaches for their practical applications. However, it has remained a great challenge to fabricate BNNS aerogels with superelasticity by a facile method. Here, we report the preparation of BNNS aerogels via a facile method involving polymer assisted cross linking and freeze casting strategies. The resulting aerogels exhibit a well ordered and anisotropic microstructure, leading to anisotropic superelasticity, high compressive strength, and excellent energy absorption ability. The unique microstructure also endows the aerogels with ultralow dielectric constant (1.24) and loss ~0.003) The successful fabrication of such fascinating materials paves the way for application of BNNSs in energy absorbing services, catalyst
author_names: Xiaoliang Zeng

Lei Ye

Shuhui Yu

Rong Sun

Jianbin Xu

Chingping Wong
title: Facile Preparation of Superelastic and Ultralow Dielectric Boron Nitride Nanosheet Aerogels via Freeze Casting Process
year: 2015

abstract: Next generation nanoelectronics based on 2D materials ideally will require reliable, flexible, transparent, and versatile dielectrics for transistor gate barriers, environmental passivation layers, capacitor spacers, and other device elements. Ultrathin amorphous boron nitride of thicknesses from 2 to 17 nm, described in this work, may offer these attributes, as the material is demonstrated to be universal in structure and stoichiometric chemistry on numerous substrates including flexible polydimethylsiloxane, amorphous silicon dioxide, crystalline Al2O3, other 2D materials including graphene, 2D MoS2, and conducting metals and metal foils. The versatile, large area pulsed laser deposition growth technique is performed at temperatures less than 200 degC and without modifying processing conditions, allowing for seamless integration into 2D device architectures. A device scale dielectric constant of 5.9 0.65 at 1 kHz, breakdown voltage of 9.8 1.0 MV cm 1, and bandgap of 4.5 eV were measured for various thicknesses of the ultrathin a BN material, representing values higher than previously reported chemical vapor deposited h BN and nearing single crystal h BN.
author_names: Nicholas R Glavin

Christopher Muratore

Michael L Jespersen

Jian-jun Hu

Phillip T Hagerty

Albert M Hilton

Austin T Blake

Christopher A Grabowski

Michael F Durstock

Michael E McConney

Drew M Hilgefort

Timothy S Fisher

Andrey A Voevodin
title: Amorphous Boron Nitride: A Universal, Ultrathin Dielectric For 2D Nanoelectronics
year: 2015

abstract: Monolayer epitaxial graphene (EG) grown on the Si face of SiC, is an advantageous material for a variety of electronic and optical applications. EG forms as a single crystal over millimeter scale areas and consequently, the large scale single crystal can be utilized as a template for growth of other materials. In this work, we present the use of EG as a template to form millimeter scale amorphous and hexagonal boron nitride (a BN and h BN) films. The a BN is formed with pulsed laser deposition and the h BN is grown with triethylboron (TEB) and NH3 precursors, making it the first metal organic chemical vapor deposition (MOCVD) process of this growth type performed on epitaxial graphene. A variety of optical and non optical characterization methods are used to determine the optical absorption and dielectric functions of the EG, a BN, and h BN within the energy range of 1 eV to 8.5 eV. Furthermore, we report the first ellipsometric observation of high energy resonant excitons in EG from the 4H polytype of SiC and an analysis on the interactions within the EG and h BN heterostructure.
author_names: Albert F Rigosi

Heather M Hill

Nicholas R Glavin

Sujitra J Pookpanratana

Yanfei Yang

Alex Boosalis

Jiuning Hu

A D Rice

A A Allerman

Nhan V Nguyen

Christina A Hacker

Randolph E Elmquist

Angela R Hight Walker

David B Newell
title: Measuring the dielectric and optical response of millimeter scale amorphous and hexagonal boron nitride films grown on epitaxial graphene.
venue: 2d materials
year: 2018

abstract: To facilitate the design of heterostructure devices employing hexagonal (sp2) boron nitride, x ray photoelectron spectroscopy has been used to determine the valence band offsets (VBOs) at interfaces between amorphous hydrogenated sp2 boron nitride (a BN:H) and atomic layer deposited high dielectric constant (high k) aluminum oxide (Al2O3) and hafnium oxide (HfO2) After consideration of the effects of charging and differential charging, including with dual beam charge compensation, the VBOs for Al2O3/a BN:H and HfO2/a BN:H interfaces were determined to be 1.9 0.2 and 1.4 0.2 eV, respectively. Additionally, the conduction band offsets at the Al2O3/a BN:H and HfO2/a BN:H interfaces were determined, based on literature reported bandgaps for the respective materials, to be 1.0 0.3 and 1.1 0.3 eV, respectively, indicating type II band alignment in both cases.
author_names: Michelle M Paquette

Anthony N Caruso

Justin Brockman

J Bielefeld

Mark Kuhn

Sean W King
title: Band offsets at amorphous hydrogenated boron nitride/high k oxide interfaces from x ray photoelectron spectroscopy with charging effects analysis
year: 2020

abstract: The physical properties in amorphous regions are important for the insulation aging assessment of polytetrafluoroethylene (PTFE) cable insulation materials. In order to study the effect of boron nitride (BN) nanoparticles on the physical properties of PTFE materials under moisture, temperature, and electric fields conditions at the molecular level, the amorphous region models of PTFE, BN/PTFE, water/PTFE, and water/BN/PTFE were respectively constructed by molecular dynamics (MD) simulation. The mechanical properties including Young's modulus, Poisson's ratio, bulk modulus, and shear modulus, along with glass transition temperature, thermal conductivity, relative dielectric constant, and breakdown strength of the four models have been simulated and calculated. The results show that the mechanical properties and the glass transition temperature of PTFE are reduced by the injection of water molecules, whereas the same, along with the thermal conductivity, are improved by incorporating BN nanoparticles. Moreover, thermal conductivity is further improved by the surface grafting of BN nanoparticles. With the increase of temperature, the mechanical properties and the breakdown strength of PTFE decrease gradually, whereas the thermal conductivity increases linearly. The injection of water molecules increases the water content in the PTFE materials, which causes a gradual increase in its relative dielectric constant. This work has shown that this effect is significantly reduced by incorporation of BN nanoparticles. The variation of physical properties for PTFE and its composites under the action of moisture, temperature, and electric fields is of great significance to the study of wet, thermal, and electrical aging tests as well as the life prediction of PTFE cable insulation materials.
author_names: Xu Hua

Li Wang

Shanshui Yang
title: Molecular Dynamics Simulation of Improving the Physical Properties of Polytetrafluoroethylene Cable Insulation Materials by Boron Nitride Nanoparticle under Moisture Temperature Electric Fields Conditions
venue: Polymers
year: 2019

abstract: We report the dependence of the thickness of amorphous boron nitride (a BN) on the characteristics of conductive bridge random access memory (CBRAM) structured with the Ag/a BN/Pt stacking sequence. The a BN thin film layers of three different thicknesses of 5.5, 11, and 21.5 nm were prepared by the sputtering deposition. Depending on the thickness of the a BN layer, the devices are found to be in either low resistance state (LRS) or high resistance state (HRS) prior to any consecutive switching cycle. All devices with 5.5 nm thick a BN switching layer are in LRS as the pristine state, while devices with 21.5 nm thick a BN layer are found to be in HRS as the pristine state. To attain reliable switching cycles, initial RESET and electroforming process are necessarily required for the devices with 5.5 and 21.5 nm thick a BN layer, respectively. However, the devices with the a BN layer of thickness between 5.5 and 21.5 nm in pristine states are in either HRS or LRS. This dependence of the a BN thickness on different resistance states in the pristine state can be explained by in situ Ag diffusion during its sputter deposition to form a top electrode on the a BN layer. Our finding shows a detailed investigation and a deep understanding of the switching mechanism of Ag/a BN/Pt CBRAM devices with respect to different a BN thicknesses for the future computing system.
author_names: Yu-Rim Jeon

Yawar Abbas

Andrey Sergeevich Sokolov

Sohyeon Kim

Boncheol Ku
title: Study of in Situ Silver Migration in Amorphous Boron Nitride CBRAM Device.
venue: ACS applied materials interfaces
year: 2019

abstract: Sputtering is the method widely used to fabricate thin films including nitrides in spintronic research fields. One of the issues to fabricate the nitride thin films via sputtering is the control of N deficiency. In this work, it was demonstrated that the use of atomic diffusion improved the insulating property of amorphous BN (a BN) BN deposition caused the nitridation of Co underlayer, and the diffusion of N from Co N into BN reduced the N deficiency of BN. The a BN formed via this sequence showed flat interfaces and no pinholes and could be used as a tunneling barrier layer. This provides an insight into synthesizing stoichiometric BN thin films. A negative tunnel magnetoresistance (TMR) ratio of 0.2% was observed at room temperature. The TMR ratio increased with a decrease in temperature to 0.7% at 10 K. The effective thickness and height of the barrier were estimated to be 1.78 nm and 0.52 eV, respectively, for 2 nm thick BN MTJs based on the dependences of transport properties on the bias voltage
author_names: Tomohiro Ichinose

Kelvin Elphick

Atsufumi Hirohata

Shigemi Mizukami
title: Tunnel Magnetoresistance in the Magnetic Tunnel Junctions with an Amorphous Boron Nitride Barrier Formed via Nitrogen Diffusion
venue: ACS Applied Electronic Materials
year: 2019

author_names: Nicholas R Glavin

Christopher Muratore

Michael L Jespersen

Phillip T Hagerty

Albert M Hilton

Austin T Blake

Christopher A Grabowski

Michael F Durstock

Michael E McConney

Drew M Hilgefort

Timothy S Fisher

Andrey A Voevodin
title: Nanoelectronics: Amorphous Boron Nitride: A Universal, Ultrathin Dielectric For 2D Nanoelectronics (Adv. Funct. Mater. 16/2016)
year: 2016