论文部分内容阅读
单晶硅变成多孔硅是在HF溶液中用阳极氧化来实现的。业已报导多孔硅由于氧化速率高而被用于IC器件的绝缘隔离。然而在氧化一段时间之后,在多孔硅和本体硅上面的二氧化硅表面间的高度差就成为一个问题了。其多孔性取决于阳极氧化的条件。在低电压情况下,反应层呈现无定形,而在较高电压的情况下用n型衬底阳极氧化,其反应层表现出单晶结构。本文叙述高度差的产生机构和多孔硅的氧化过程,特别是对于在低电流情况下形成的多孔硅。硅片系采用在P型、10～20欧姆·厘米、<111>取向的衬底上的n型、0.2～0.3欧姆·厘米、3微米厚的外延层。硼选择地通过n型外延层扩散到p型衬底。然后,硅片
The conversion of monocrystalline silicon into porous silicon is achieved by anodization in HF solution. It has been reported that porous silicon is used for the insulation of IC devices due to the high oxidation rate. However, after a period of oxidation, the height difference between the surface of the silica on the porous silicon and the bulk silicon becomes a problem. Its porosity depends on the conditions of the anodization. At low voltage, the reaction layer appears amorphous, whereas in the case of higher voltages it is anodized with an n-type substrate, the reaction layer of which shows a single crystal structure. This article describes the height difference generating mechanism and the oxidation of porous silicon, especially for porous silicon formed at low current. The silicon wafer is an n-type, 0.2-0.3 ohm.cm, 3 micron thick epitaxial layer on a p-type, 10-20 ohm.cm, <111> oriented substrate. Boron selectively diffuses through the n-type epitaxial layer to the p-type substrate. Then, silicon