利用半导体pn结结电容构成的沟道式电容器

Trench capacitors based on semiconductor pn junction capacitance

为满足对电子系统中元器件性能提升、面积减小、成本降低等需求,利用感应耦合等离子体刻蚀技术(ICP),对低阻p型硅采用刻蚀、扩散、磁控溅射Al电极等工艺,使之形成凹槽状三维结构,制造出一种特殊的具有高密度电容量的硅基电容器。其特点是结构简单,电容量大(电容密度可达2.2×10–9F/mm2),容值可调,与现有微电子工艺兼容,可用于200MHz至数GHz的退耦或其他场合。同时由于半导体pn结固有的特性,该电容器可取代传统的贴片电容广泛用于电子系统中的退耦、滤波、匹配、静电和电涌防护等场合。

Nowadays, high performance, small size and low cost are always required by modem electronic systems. A new technology for fabricating decoupling capacitor on silicon chip was developed. In this method, trenches with quasi-3D structure were first formed on the silicon substrate through performing inductively coupled plasma （ICP） etching. After conducting doping via diffusion, fabricating A1 electrode through sputtering and etching, a kind of silicon based capacitor with high capacitance density was formed on the trenches. The prepared capacitors show simple structure, large and adjustable capacitance, and good compatibility with existing microelectronic technologies. They can be used for decoupling in the range of 200 MHz to 1 - 10 GHz. And, because of the characteristics of semiconductor, they can be used for ESD and surge protection which are impossible for conventional capacitors. As a replacement of conventional SMT capacitors, this kind of capacitor can be widely used for decoupling, filtering, ESD as well surge protection and matching in the electronic systems.