Development of Heteroepitaxial Diamond Thin Films as Novel Semiconducting Materials

异质外延金刚石薄膜作为新型半导体材料的开发

基本信息

批准号：
07555240
负责人：
MOROOKA Shigeharu
金额：
$ 11.65万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

We produced diamond thin films on (100) and (111) silicon or diamond crystals by microwave plasma-assisted chemical vapor deposition method and developed applications of the films as semiconducting materials.The quality of heteroepitaxial diamond films was strongly affected by orientation of diamond nuclei formed in the very early stage of the deposition. We examined the mechanism of the nucleation in detail, and developed a novel "double-step bias treatment process." We also showed that propylene was superior to methane as the carbon source. By optimizing deposition conditions, we successfully improved the fraction of oriented diamond particles in the nucleation stage up to 60% from the original fraction of 40%.Semiconducting properties of diamond films are dependent on dopants and doping conditions. Although diborane and phosphine are typically used as the boron and phosphorus dopants, respectively, they are very difficult to handle because of toxicity and flammability. We discovered … More that trimethylboron (TMB) and triethylphosphine (TEP) possessed low toxicity and flammability as well as appropriate vapor pressures. We determined the growth rates on the (100) and (111) diamond faces as functions of substrate temperature and methane and TMB or TEP concentrations. B-and P-doped diamond films which were thus formed on (100) and (111) diamond single crystal substrates were characterized by high-resolution scanning electron microscopy, Raman spectroscopy, secondary ion mass spectroscopy and reflection high energy electron diffraction. Semiconductive properties of the films were evaluated by Hall effect examination.Diamond films, which were formed on (100) and (111) diamond crystals using TMB as the boron source were smooth and homoepitaxial. Boron was incorporated in the diamond films homogeneously, and the width of the diamond peak detected by Raman spectroscopy was equivalent to that of natural diamond. The mobility of the TMB-doped film was 300 cm^<2.>V^<-1.>s^<-1> at a hole concentration of 3*10^<13> cm^<-3>, and the activation energy for conductivity in the range of 200-293 K was approximately 0.2eV.Both were lower than those reported with diamond films doped with diborane. The TEP-doped diamond film showed a high resistivity. These results will be improved by further optimizing deposition conditions. Less

采用微波等离子体辅助化学气相沉积方法在(100)和(111)硅或金刚石强晶体上制备金刚石薄膜，并开发薄膜在半导体材料中的应用。异质外延金刚石薄膜的质量受金刚石核取向的影响我们详细研究了成核机制，并开发了一种新颖的“双步偏压处理工艺”，我们还表明丙烯作为碳源优于甲烷。通过优化沉积条件，我们成功地将成核阶段定向金刚石颗粒的比例从原来的 40% 提高到 60%。尽管通常使用乙硼烷和磷化氢，但金刚石薄膜的半导体性能取决于掺杂剂和掺杂条件。分别作为硼和磷掺杂剂，由于毒性和易燃性，它们非常难以处理。我们发现三甲基硼 (TMB) 和三乙基膦 (TEP) 具有低毒性和易燃性以及适当的蒸气压，我们确定了 (100) 和 (111) 金刚石表面上的生长速率与基底温度和甲烷以及 TMB 或 TEP 浓度的关系。通过高分辨率扫描电子显微镜、拉曼光谱、二次离子质量对在（100）和（111）金刚石单晶基底上形成的掺杂金刚石薄膜进行了表征以TMB为硼源在(100)和(111)金刚石晶体上形成的金刚石薄膜光滑且掺入了硼。金刚石薄膜中分布均匀，拉曼光谱检测到的金刚石峰宽度与天然金刚石相当，TMB掺杂薄膜的迁移率为300。 cm^<2.>V^<-1.>s^<-1> 空穴浓度为 3*10^<13> cm^<-3> 时，电导率活化能范围为 200- 293 K 约为 0.2eV。两者均低于掺杂乙硼烷的金刚石薄膜。这些结果将通过进一步优化沉积条件得到改善。