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New Technique to Grow High Quality SOI layer

生长高质量 SOI 层的新技术

基本信息

批准号：
62850052
负责人：
NISHINAGA Tatau
金额：
$ 14.53万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research
财政年份：
1987
资助国家：
日本
起止时间：
1987 至 1989
项目状态：
已结题

项目摘要

High quality SOI film was obtained by epitaxial lateral overgrowth (ELO) with LPE. Since LPE is carried out with almost thermally equilibrium process, it has three advantages as follows: (1) Good crystal quality (2) Large ratio of lateral width to vertical thickness (ELO ratio) (3) High flatness because the grown surface is covered with a facet. For ELO, the substrate is limited to the (111) surface. Sn was used as a solvent.First, the growth mechanism of the ELO was studied. It was found that in the circular seeds the growth occurred at steps which were supplied not only by screw dislocations and the misoriented substrate but also by 2D nucleation. Growth from the line seeds was found to occur almost at steps supplied by the misoriented substrate, while sometimes the screw dislocation was introduced at the periphery of the ELO where 2D cellular structure was formed because of the morphological instability. It was found that it is important to keep the supersaturation as low as possible to prevent morphological instability. ELO ratio was improved to 75 and the step free facet was obtained at the optimum condition.Second, the technique to control ELO thickness was developed. ELO layer was grown from a ridge seed. Its thickness was same as the height of the ridge. Therefore, ELO thickness can be controllable by adjusting the height of the ridge. 0.23 um thick layer was grown and ELO thickness was shown to be controllable to the order of 100 nm. With this technique the ELO ratio was improved to 163.Finally, crystal quality of ELO layer was evaluated by Sirtl etching. Dislocations were completely eliminated by the growth at the low supersaturation. This result indicates that the ELO layer has a good crystal quality.In summary, new technique has been developed for obtaining high quality SOI layer by using LPE lateral overgrowth.

采用LPE外延横向过生长（ELO）法制备了高质量的SOI薄膜。由于LPE几乎是在热平衡过程中进行的，因此它具有以下三个优点：(1)晶体质量好；(2)横向宽度与垂直厚度的大比（ELO比）；(3)由于生长表面覆盖了一个facet，因此平整度高。对于ELO，衬底限于（111）表面。以锡为溶剂。首先，研究了ELO的生长机理。结果表明，在圆形种子中，生长过程不仅由螺旋位错和取向错误的底物提供，而且还由二维形核提供。从线种子生长几乎发生在取向错误的底物提供的步骤中，而有时在ELO的外围引入螺旋位错，在那里由于形态不稳定而形成二维细胞结构。研究发现，保持过饱和度尽可能低是防止形态不稳定的重要因素。将ELO比提高到75，并在最佳条件下获得无阶跃面。其次，开发了ELO厚度控制技术。ELO层是由山脊种子生长而来。它的厚度与山脊的高度相同。因此，可以通过调整脊的高度来控制ELO的厚度。生长了0.23 um厚的ELO层，ELO厚度可控制在100 nm量级。采用该技术，ELO比提高到163。最后，用Sirtl刻蚀法评价了ELO层的晶体质量。低过饱和度下的生长完全消除了位错。结果表明，该ELO层具有良好的晶体质量。总之，开发了利用LPE横向过生长获得高质量SOI层的新技术。