A Study on Ultrafine Doping by Focused Ion Beam Implantation

1. 聚焦离子束（FIB）装置的研制在高真空室中开发了各种离子的液态金属离子源，以延长其寿命。结果表明，通过ExB质滤器可以选择所需的离子种类，聚焦到直径为0.1 um的范围内，并通过计算机控制精确偏转。研究了一种激活注入砷化镓中的Si离子的瞬态退火技术。霍尔和光致发光测量表明，退火过程中产生的SiAs和GaAs受体影响了活化效率。FIB注入区表征聚焦Si离子和Be离子注入GaAs，最高效率分别为40%和90%。这些值与传统植入的值是一致的。然而，在超过60秒的退火时间后，发现Be原子异常扩散。提出了利用FIB植入制备小区域、横向和垂直jfet的新型功能器件。这些装置是通过计算注入离子在gaas中的分布来设计的。高剂量小区域注入制备新材料聚焦镓离子注入InP形成GaInP合金半导体。光学测量表明，合金的GaInP已部分形成。然而，植入层中出现了多晶化现象和ga聚类现象。

1. Development of Focused Ion Beam (FIB) ApparatusLiquid Metal Ion Source for various ions were developed in high vacuum chamber to prolong the lifetimes. It was confirmed that desired ion species could be selected by ExB mass-filter, focused into 0.1 um diameter and deflected precisely by computer control.2. Transient AnnealA transient anneal technique was developed to activate implanted Si ion in GaAs. Hall and photoluminescence measurements revealed that SiAs and GaAs acceptors, which were created during anneal, affected the activation efficiency.3. Characterization of FIB implanted regionsFocused Si and Be ions were implanted into GaAs and maximum efficiency of 40% and 90% were obtained, respectively. These values are compatible to those for conventional implantations. However, Be atoms were found to anomalously diffuse after longer annealing than 60 sec.4. Fabrication of new functional devices by FIB implantation into small regionsLateral- and vertical-JFETs, which can be fabricated by FIB implantation, were proposed. These devices were designed by calculating distributions of implanted ions in GaAs.5. Fabrication of new materials by high-dose implantation into small regionsFocused Ga ions were implanted into InP to form GaInP alloy semiconductors. It was revealed by optical measurements that the alloyed GaInP was partly formed. However, poly-crystallization of implanted layers and Ga-clustering were observed.