Investigation of low-resistivity from hydrogenated lightly B-doped diamond by ion implantation

Abstract

We have implanted boron (B) ions (dosage: 5×10¹⁴ cm^-2) into diamond and then hydrogenated the sample by implantating hydrogen ions at room temperature. A p-type diamond material with a low resistivity of 7.37 mΩ cm has been obtained in our experiment, which suggests that the hydrogenation of B-doped diamond results in a low-resistivity p-type material. Interestingly, inverse annealing, in which carrier concentration decreased with increasing annealing temperature, was observed at annealing temperatures above 600 °C. In addition, the formation mechanism of a low-resistivity material has been studied by density functional theory calculation using a plane wave method.     

Application of N- and B-doped CVD diamond layers for cyclic voltammetry measurements

Conductive polycrystalline diamond layers prepared by the CVD process have received attention from electrochemists owing to such superior electrochemical properties as the wide potential window, the very low background current, the stability of chemical and physical properties.In this paper, the cyclic voltammetry application using N- and B-doped diamond electrodes was studied. Diamond layers, doped with boron and nitrogen, were synthesized on a silicon substrate in a hot-filament CVD reactor. The obtained diamond layers were characterized using Raman spectroscopy and scanning electron microscopy (SEM).The electrochemical properties of diamond layers were measured in KCl and NaCl basic solutions to gain knowledge about their potential application as an electrode material.It was found that boron doped diamond electrodes showed potential windows up to about 7 V which were almost twice wider than those observed for conventional Pt electrodes.     

燃焰法沉积金刚石薄膜的均匀性研究

研究了燃焰法沉积金刚石薄膜的质量均匀性,指出反应气体流量比是影响金刚石薄膜质量均匀性的主要因素,基片表面沉积区径向温度梯度使金刚石膜晶粒尺寸偏离沉积中心距离的增加而减小。     

Tribology of amorphous diamond films grown or modified by ion implantation

The friction and wear resistances of amorphous diamond films grown by quenching of an intense laser-plasma or by ion implantation were correlated to their thickness and structure. Their adherence to a Ti_0.85Al_0.11V_0.04 alloy is assisted by an interfacial layer of TiC precipitates. This adherence can be improved by a further irradiation promoting the growth of the Ti-TiC composite layer by radiation-enhanced diffusion in the metallic matrix. Nitrogen implantation in the substrate has an additional catalytic effect on the carbide nucleation. However, damaging the carbon film itself or doping it with nitrogen do not improve the mechanical properties and are rather detrimental for electronic properties.     

掺氮N型纳米金刚石薄膜的电化学表面氢化及表征

针对掺氮N型纳米金刚石薄膜独特的结构特征,采用温和的电化学阴极表面极化处理成功实现了掺氮N型纳米金刚石薄膜的表面氢化。通过X射线光电子能谱(XPS)、表面接触角、电化学电容-电压分析、Raman光谱、扫描电子显微镜(SEM)表征,详细分析了阴极极化处理前后掺氮N型纳米金刚石薄膜的表面结构以及微观结构。结果表明,该阴极极化处理工艺不仅能够成功获得表面氢终止状态,而且对薄膜的微观结构尤其是晶界处sp2杂化态碳相无明显影响,说明该工艺是一种高效无损的掺氮N型纳米金刚石薄膜表面氢化工艺。     

形核工艺对金刚石膜形貌和电阻率的影响

金刚石薄膜电阻率的高低是薄膜绝缘性能优劣的直观反映,也是影响辐射剂量计器件性能的重要因素.针对目前形核工艺与电阻率的关系还不十分清楚的问题.本文研究了微波等离子体形核阶段工艺参数如基片位置、微波功率、甲烷浓度的变化对金刚石薄膜的表面形貌和电阻率的影响.结果表明微波等离子体形核工艺参数对金刚石薄膜的电阻率和表面形貌有显著影响.获得的最佳成核工艺条件:基体温度960℃、甲烷浓度0.72%、压力5.3 kPa、微波功率1300 W.在此工艺条件下制得的金刚石薄膜的电阻率值达到1011 Ω·cm数量级.     

自支撑金刚石厚膜脱离基体前后的残余应力研究

运用ANSYS软件建立了有限元模型,对直流等离子体喷射制备的自支撑金刚石厚膜在脱离基体前、后的残余应力分别进行了数值模拟。为了使模拟更接近于金刚石膜的真实制备环境,本文取消了以往对金刚石膜或基体内的温度场常作的均匀或线性的人为假设,而采用对从磁控直流等离子体炬内喷射出的射流仿真计算结果。结论如下(:1)金刚石膜脱离基体之前,金刚石厚膜内的热残余应力呈空间应力状态,第一主应力在膜层中心以外的大部分地方均为拉应力,易引起膜开裂破坏;膜/基界面上极大的剪切应力是引起金刚石膜从基体上脱离的主要原因。(2)金刚石膜脱离基体之后,热残余应力绝大部分被释放,膜内最终的残余应力可认为是本征应力。     

金属离子注入聚合物光电特性研究

采用MEVVA离子注入机引出的Cu和Ni离子注入聚酯薄膜，注入后的聚酯膜极大降低了聚酯膜的电阻率。注入表面紫外线和红外线吸收特性明显增强。用透射电子显微镜观察注入聚酯膜的横截面，TEM观察表明，在注入层中形成了纳米金属颗粒和富集的碳颗粒。注入层的结构的变化和新相的形成引起了聚合物表面物理和化学特性的改变，进而讨论了金属离子注入聚酯膜的改性机理。     

多层式金刚石薄膜的制备工艺研究

利用热丝化学气相沉积(HFCVD)技术,通过逐次调整气压、碳源浓度等生长参数,沉积了晶粒尺寸逐层减小的多层式金刚石薄膜.场发射扫描电镜(FE-SEM)和原子力显微镜(AFM)测试显示其表层晶粒平均尺寸约为20nm,厚度和表面平均粗糙度分别为35.81μm和18.8nm(2μm×2μm),皆能满足高频声表面波器件用衬底的要求.实验结果表明,多层式生长方法是制备声表面波器件用金刚石衬底的理想方法.     

Spectroellipsometric and ion beam analytical investigation of nanocrystalline diamond layers

Optical properties of nanocrystalline and ultrananocrystalline diamond films were studied by ex situ variable angle spectroscopic ellipsometry. The films were prepared by Microwave Plasma Enhanced Chemical Vapor Deposition method. In the experiments Ar, CH₄, and H₂ gases were used as source gases. Elastic recoil detection analysis was applied to measure the hydrogen content of the deposited layers. Three-layer optical models were constructed for the evaluation of the measured ellipsometric spectra. Besides the Cauchy relation, the effective medium approximation and the Tauc-Lorentz dispersion relation were also used for the modeling of the optical properties of the diamond films. Atomic force microscopy was applied to investigate the surface roughness in function of the deposition conditions.     

金刚石膜中黑色缺陷形成过程的计算机模拟

多晶金刚石膜中的黑色缺陷是影响材料光学、电学性能的一种重要缺陷。利用水平集方法对黑色缺陷的形成过程进行了模拟。模拟的基本假设为:黑色缺陷形成的基本条件为相邻晶粒间的晶界环境使活性气体扩散的过程难以进行,形成了一种形如峡谷状的、相邻晶面夹角30°的局部环境。金刚石膜的生长参数α2d值由1.3改变为1.5,在其晶粒表面{11}面上形成孪晶。孪晶的长大促进了黑色缺陷的形成。     

非晶金刚石离子镀膜机自动化控制系统的设计

结合非晶金刚石离子镀膜机的工艺特点和要求，本文介绍了一种成功应用的分布式控制系统的设计，重点讨论了控制系统的硬件配置、软件设计、通信服务程序以及软件编程中的几个控制算法。     

高压熔渗金刚石/铜复合材料的低温导热特性

为研究高压熔渗金刚石/铜复合材料导热率在低温区的变化规律,采用高压熔渗（HRF）的方法分别制备了不同粒度（100 μm,250 μm,400 μm）的金刚石/铜复合材料,利用扫描量热法分析评价了高压熔渗法制备的不同粒度金刚石/铜复合材料的低温导热特性,采用扫描电子显微镜（SEM）分析其显微组织。研究结果表明：由于高压熔渗制备的金刚石/铜复合材料中的部分金刚石发生聚晶反应,导致金刚石颗粒间晶界传热的热阻远小于界面传热热阻;高压熔渗条件下,金刚石颗粒内部变形破碎导致缺陷增多,且100~150 K低温下以声子为主要热载子的传热对裂纹和间隙等缺陷敏感,导致在较低温区内金刚石/铜复合材料的导热率低于普通压力熔渗（PF）所制备的金刚石/铜复合材料的导热率。     

用激光法合成纳米金刚石

使脉冲激光与石墨粉在空气中相互作用,并对其氧化提纯．对产物进行的显微激光拉曼光谱（Raman）与高分辨电子显微镜（HRTEM）分析表明,产物中含大量纳米金刚石颗粒,其尺寸为5nm左右,且具有较多的晶体缺陷和残余内应力．提出了石墨转变为金刚石纳米晶的机理：在脉冲激光产生的高温高压的条件下,具有石墨结构的原子团发生快速滑移切变,形成立方金刚石晶核,碳等离子体中高化学活性的碳粒子集团使金刚石晶核迅速长大,形成金刚石微晶．     

金刚石厚膜的晶界对耐磨性的影响

用直流辉光等离子体化学气相沉积制备金刚石厚膜,用氢的微波等离子体对其抛光截面进行刻蚀,研究了晶界对金刚石厚膜耐磨性的影响.结果表明：在金刚石膜的生长过程中,随着甲烷流量的增加,金刚石膜的晶界从纵向排列为主过渡到网状结构,晶粒内部缺陷逐渐增加,杂质、空洞主要分布于晶界处．金刚石膜的磨耗比随着晶界密度、宽度、杂质含量及晶粒内部缺陷的增加而下降．晶界是杂质、空洞主要富集区,是影响金刚石厚膜耐磨性的主要因素．     

热丝碳化促进CVD金刚石成核增强的物理机制

采用扫描电镜、X射线衍射及喇曼光谱等手段研究了HFCVD过程中热丝碳化对金刚石成核特性的影响。热丝经充分碳化后能发射出更多热电子，进而从反应气体中激发出更多原子H和CH3^ ，使金刚石晶核的孕育期大为缩短，3min内即可在未经表面预处理Si衬底上获得10^10cm^-2以上的高晶核密度。     

The contribution of ion plasma sprayed coatings to performance of diamond dressing tools

The paper addresses the effect of ion plasma sprayed coatings on performance of diamond dressing tools under diamond abrasive machining conditions. The use of thick wear-resistant titanium nitride and carbide coatings with a compensating interlayer of a plastic metal (cobalt) is demonstrated to be a promising method for improving efficiency of dressing tools manufactured by electroplating and electroforming.     

基体温度对金刚石厚膜沉积质量的影响

为探讨燃焰法沉积高质量金刚石厚膜的可能及其沉积速率，在反应气体流量比O2／C2H2=0．97～1范围内，研究了基体温度对燃焰法沉积金刚石厚膜的影响．结果表明，基体温度在610～730℃范围内可沉积出均匀、致密、结晶形态优良的金刚石厚膜；金刚石厚膜沉积速率随基体温度的下降而下降，基体温度约为730℃时，可以约50μm／h的较高速率沉积出淡黄色透明状高质量金刚石厚膜．当基体温度在820℃左右的高温时，金刚石厚膜不均匀，晶粒间存在较大间隙，且在金刚石厚膜生长过程中，存在较多的二次成核。     

Thermal diffusivity measurement of CVD diamond film using a step heating technique

A step heating method for the measurement of the thermal diffusivity of diamond thin film is described. The step heating method is a transient heat flow method. Transient temperature profiles are generated in a strip-shaped sample by heating one end of the sample while the other end is clamped to a heat sink. Three thermocouples are used along the heat path. The results are compared with the literature values over the temperature range from –190 to 50°C.     

UHV/CVD硅外延的实时硼掺杂研究

本文利用超高真空化学气相沉积系统 (UHV CVD)在 72 0℃Si(10 0 )衬底上进行了实时B掺杂的硅外延。采用二次离子质谱仪 (SIMS) ,傅立叶红外光谱 (FTIR) ,扩展电阻仪 (SRP)对外延层的性能进行研究。研究表明 :72 0℃生长时已经实时掺入了B原子 ,10 0 0℃退火 5分钟后 ,外延层中B原子被激活 ,浓度达到 10 17～ 10 18cm-3 ,且过渡层分布陡峭