Schottky Barrier Diodes（SBD）肖特基势垒二极管

肖特基势垒二极管（Schottky Barrier Diodes），又称热载流子二极管。利用金属-半导体(M-S)接触特性制成，有点接触型和面结合型两种管芯结构。

Schottky Barrier Diodes, also known as hot carrier diodes, are made using the metal-semiconductor (M-S) junction contact characteristic. There are two core structures: point contact type and surface junction type.

肖特基势垒二极管利用金属-半导体(M-S)接触特性制成，由于金属-半导体接触的电流运输主要是依靠多数载流子(电子)，其电子迁移率高，且M-S结可以在亚微米尺度上精确制造加工，使得肖特基势垒二极管能运用到亚毫米波、太赫兹波频段。肖特基势垒二极管基本结构如图1所示。

Schottky Barrier Diodes are made using the metal-semiconductor (M-S) junction contact characteristic. Due to the fact that the current transport at the metal-semiconductor interface primarily relies on majority carriers (electrons), which have high electron mobility, and because M-S junctions can be precisely manufactured and processed at the submicron scale, Schottky Barrier Diodes can be used in the submillimeter and terahertz frequency ranges. The basic structure of a Schottky Barrier Diode is shown in Figure 1.

由于N型掺杂相比于P型掺杂有更高的电子迁移率，衬底材料选择“N+型”衬底，随后在衬底表面生长出一层高纯度、高电导率的N型重掺杂缓冲层，用于保证较低的串联电阻及防止衬底杂质进入外延层。外延层生长在缓冲层上表面，其掺杂浓度与厚度是二极管的重要设计参数。外延层上表面与金属阳极接触形成肖特基势垒接触，形成整流结，在衬底下表面与金属阴极接触形成欧姆接触。 

Due to the higher electron mobility of N-type doping compared to P-type doping, an "N+ type" substrate is chosen as the substrate material. Subsequently, a layer of high purity and high conductivity N-type heavily doped buffer layer is grown on the substrate surface to ensure lower series resistance and prevent substrate impurities from entering the epitaxial layer. The epitaxial layer is grown on the surface of the buffer layer, and its doping concentration and thickness are important design parameters for the diode. The surface of the epitaxial layer forms a Schottky barrier contact with the metal anode, creating a rectifying junction, while the bottom surface contacts the metal cathode to form an ohmic contact.

肖特基势垒二极管有两种管芯结构：点接触型和面结合型，如下图2所示。点接触型管芯用一根金属丝压接在N型半导体外延层表面上形成金半接触。面结合型管芯先要在N型半导体外延层表面上生成二氧化硅保护层，再用光刻的办法腐蚀出一个小孔，暴露出N型半导体外延层表面，淀积一层金属膜（一般采用金属泪或钛，称为势垒金属）形成金半接触，再蒸馏或电镀一层金属（金、银等）构成电极。

Schottky Barrier Diodes have two core structures: point contact type and surface junction type, as shown in Figure 2. In the point contact core structure, a single metal wire is pressed onto the surface of the N-type semiconductor epitaxial layer to form a metal-semiconductor contact. In the surface junction core structure, a silicon dioxide protective layer is first generated on the surface of the N-type semiconductor epitaxial layer. Then, a small hole is etched out using photolithography, exposing the surface of the N-type semiconductor epitaxial layer. A layer of metal film (commonly using metal such as aluminum or titanium, known as the barrier metal) is deposited to form a metal-semiconductor contact, and another layer of metal (gold, silver, etc.) is either evaporated or electroplated to form the electrode.

考虑封装对管芯参数造成的影响，肖特基势垒二极管的等效电路如图所示。

Taking into consideration the impact of packaging on core parameters, the equivalent circuit of a Schottky Barrier Diode is as shown in the diagram.