Plasma-Immersion Ion Implantation
Plasma-Immersion Ion Implantation
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DOI：
10.1557/s0883769400035727
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发表时间：
1996-08
期刊：
影响因子：
5
通讯作者：
J. Mantese;I. Brown;N. Cheung;George A. Collins
中科院分区：
文献类型：
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作者：
J. Mantese;I. Brown;N. Cheung;George A. Collins
等离子体浸没离子注入（PIII）是一种新兴的半导体、金属和陶瓷表面工程技术。它本质上是一种可批量处理的技术，适合于同时植入大量部件。因此，它提供了将离子注入引入到传统上使用常规注入不可行的制造工艺中的可能性。在PIII中，将待处理的部件放置在真空室中，在该真空室中产生包含待注入物质的离子的等离子体。基于等离子体的注入系统不使用常规质量分析质谱仪的提取和加速方法。相反，样品（通常）在高负电压（2-300 kV范围内）下重复脉冲，以用高能等离子体离子流注入表面，如图1所示。当负偏压施加到浸没在等离子体中的导电物体上时，电子从周围区域被排斥到真空室的壁，真空室通常保持在地电位。几乎所有施加的电压差都发生在该区域上，该区域通常被称为鞘层或阴极下降区域。离子加速穿过鞘层，产生离子流到工件的整个暴露表面。因为等离子体围绕样品，并且因为离子垂直于样品表面被加速，所以在所有表面上发生注入，从而消除了对束线扫描器通常所需的精细靶操纵或掩蔽系统的需要。注入工件中的离子必须在鞘层边界处被进入的离子流所取代，否则鞘层将继续膨胀到周围的等离子体中。等离子体密度保持相对较低，通常在10 8和10 11离子/cm 3之间。离子必须通过扩散或电离在工件附近补充，因为工件（实际上）表现得像离子泵。气体放电的电子，射频或微波电离源已成功地使用。表面增强材料是通过PIII通过产生化学和微观结构变化而获得的，这些变化导致改变的电性能（例如，半导体应用），以及低摩擦和超硬表面，耐磨和耐腐蚀。当PIII仅限于气态注入物质时，这些独特的表面性质主要通过氮化物、氧化物和碳化物的形成来获得。当应用于半导体应用时，PIII可用于形成非晶和电掺杂层。等离子体浸没离子注入也可以与等离子体沉积技术相结合，以产生具有增强性能的涂层，例如类金刚石碳（DLC）。PIII的后一种变体可以在高离子能状态下操作，以便进行离子混合并形成高度粘附的膜，并且可以在类似离子束辅助沉积（IBAD）的离子能状态下操作，以产生良好的膜形态和结构。
Plasma-immersion ion implantation (PIII) is an emerging technology for the surface engineering of semiconductors, metals, and dielectrics. It is inherently a batch-processable technique that lends itself to the implantation of large numbers of parts simultaneously. It thus offers the possibility of introducing ion implantation into manufacturing processes that have not traditionally been feasible using conventional implantation. In PIII the part to be treated is placed in a vacuum chamber in which is generated a plasma containing the ions of the species to be implanted. The plasma based implantation system does not use the extraction and acceleration methods of conventional mass-analyzing implanters. Instead the sample is (usually) repetitively pulsed at high negative voltages (in the 2–300 kV range) to implant the surface with a flux of energetic plasma ions as shown in Figure 1. When the negative bias is applied to a conducting object immersed in a plasma, electrons are repelled from the surrounding region toward the walls of the vacuum chamber, which is usually held at ground potential. Almost all the applied voltage difference occurs across this region, which is generally known as a sheath or cathode fall region. Ions are accelerated across the sheath, producing an ion flux to the entire exposed surface of the work-piece. Because the plasma surrounds the sample and because the ions are accelerated normal to the sample surfaces, implantation occurs over all surfaces, thereby eliminating the need for elaborate target manipulation or masking systems commonly required for beam line implanters. Ions implanted in the work-piece must be replaced by an incoming flow of ions at the sheath boundary, or the sheath will continue to expand into the surrounding plasma. Plasma densities are kept relatively low, usually between 10 8 and 10 11 ions per cm 3 . Ions must be replenished near the workpiece by either diffusion or ionization since the workpiece (in effect) behaves like an ion pump. Gaseous discharges with thermionic, radio-frequency, or microwave ionization sources have been successfully used. Surface-enhanced materials are obtained through PIII by producing chemical and microstructural changes that lead to altered electrical properties (e.g., semiconductor applications), and low-friction and superhard surfaces that are wear- and corrosion-resistant. When PIII is limited to gaseous implant species, these unique surface properties are obtained primarily through the formation of nitrides, oxides, and carbides. When applied to semiconductor applications PIII can be used to form amorphous and electrically doped layers. Plasma-immersion ion implantation can also be combined with plasma-deposition techniques to produce coatings such as diamondlike carbon (DLC) having enhanced properties. This latter variation of PIII can be operated in a high ionenergy regime so as to do ion mixing and to form highly adherent films, and in an ion-beam-assisted-deposition (IBAD)-like ion-energy regime to produce good film morphology and structure.