肖特基二极管

肖特基二极管简介

肖特基二极管（SBD）是肖特基势垒二极管（SchottkyBarrierDiode，缩写成SBD）的简称，是以其发明人肖特基博士（Schottky）命名的半导体器件。肖特基二极管是低功耗、大电流、超高速半导体器件，它不是利用P型半导体与N型半导体接触形成PN结原理制作的，而是利用金属与半导体接触形成的金属－半导体结原理制作的。因此，SBD也称为金属－半导体（接触）二极管或表面势垒二极管，它是一种热载流子二极管。

Schottky diode (SBD) is the Schottky barrier diode , is the inventor of the Schottky named semiconductor device. Schottky barrier diode is a low power, high current, super high speed semiconductor devices, instead of using P type semiconductor and the n-type semiconductor contact formation PN junction theory to make, but the use of metal semiconductor contact formation of metal semiconductor junction with the principle of making the. Therefore, SBD is also known as a metal semiconductor (contact) diode or a surface barrier diode, which is a hot carrier diode.

肖特基二极管是半导体器件，以其发明人博士（1886年7月23日—1976年3月4日）命名的，SBD是肖特基势垒二极管（SchottkyBarrierDiode，缩写成SBD）的简称。

SBD不是利用P型半导体与N型半导体接触形成PN结原理制作的，而是利用金属与半导体接触形成的金属－半导体结原理制作的。因此，SBD也称为金属－半导体（接触）二极管或表面势垒二极管，它是一种热载流子二极管。

肖特基二极管是问世的低功耗、大电流、超高速半导体器件。其反向恢复时间极短（可以小到几纳秒），正向导通压降仅0.4V左右，而整流电流却可达到几千毫安。这些优良特性是快恢复二极管所无法比拟的。中、小功率肖特基整流二极管大多采用封装形式。

Schottky diode is a semiconductor device, which is named after its inventor (March 4, 1976 - July 23, 1886), SBD is the Schottky barrier diode (SchottkyBarrierDiode, abbreviated as SBD).

SBD does not use the p-type semiconductor and the n-type semiconductor contact formation PN junction theory to make, but the use of metal semiconductor contact formation of metal semiconductor junction with the principle of making the. Therefore, SBD is also known as a metal semiconductor (contact) diode or a surface barrier diode, which is a hot carrier diode.

Schottky diode is the advent of low power, high current, ultra high speed semiconductor devices. The reverse recovery time is very short, small to a few nanoseconds) and positive guide through pressure drop of only 0.4%, and rectified current can reach thousands of Ma. These excellent properties are not comparable to the fast recovery diode. Medium and small power Schottky rectifier diodes are mostly used in package form.

原理

肖特基二极管是贵金属（金、银、铝、铂等）A为正极，以N型半导体B为负极，利用二者接触面上形成的势垒具有整流特性而制成的金属-半导体器件。因为N型半导体中存在着大量的电子，贵金属中仅有极少量的自由电子，所以电子便从浓度高的B中向浓度低的A中扩散。显然，金属A中没有空穴，也就不存在空穴自A向B的扩散运动。随着电子不断从B扩散到A，B表面电子浓度逐渐降低，表面电中性被破坏，于是就形成势垒，其电场方向为B→A。但在该电场作用之下，A中的电子也会产生从A→B的漂移运动，从而消弱了由于扩散运动而形成的电场。当建立起一定宽度的空间电荷区后，电场引起的电子漂移运动和浓度不同引起的电子扩散运动达到相对的平衡，便形成了肖特基势垒。肖特基二极管工作原理典型的肖特基整流管的内部电路结构是以N型半导体为基片，在上面形成用砷作掺杂剂的N-外延层。阳极使用钼或铝等材料制成阻档层。用二氧化硅（SiO2）来消除边缘区域的电场，提高管子的耐压值。N型基片具有很小的通态电阻，其掺杂浓度较H-层要高100%倍。在基片下边形成N+阴极层，其作用是减小阴极的接触电阻。通过调整结构参数，N型基片和阳极金属之间便形成肖特基势垒，如图所示。当在肖特基势垒两端加上正向偏压（阳极金属接电源正极，N型基片接电源负极）时，肖特基势垒层变窄，其内阻变小；反之，若在肖特基势垒两端加

上反向偏压时，肖特基势垒层则变宽，其内阻变大。综上所述，肖特基整流管的结构原理与PN结整流管有很大的区别通常将PN结整流管称作结整流管，而把金属-半导管整流管叫作肖特基整流管，采用硅平面工艺制造的铝硅肖特基二极管也已问世，这不仅可节省贵金属，大幅度降低成本，还改善了参数的一致性。

Schottky diode is a metal semiconductor device, which is formed on the surface of the two electrode, which is made of N (B) A as the cathode, and the potential barrier is formed on the contact surface. Because there are a lot of electrons in the N type semiconductor, there is only a very small amount of free electrons in the precious metal, so the electron diffusion from the B to the low concentration of A. It is clear that there is no hole in the metal A, and there is no diffusion motion of the hole from the A to the B. With the electrons from B to A, the surface electron concentration of B gradually decreases, the surface of the neutral is

destroyed, so the barrier is formed, and the electric field direction is A >

B. But under the action of electric field, the electrons in a will produce drift movement from a to B, thus weaken the due to diffusive motion and the formation of the electric field. When the space charge region of a certain width is set up, the electron drift caused by the electric field and the concentration of the electron diffusion motion caused by the different concentration of the electric field can reach the equilibrium, and Schottky barrier.The internal circuit structure of the Schottky diode is typical of the internal structure of the Schottky rectifier tube is a N type semiconductor as the substrate, and the formation of the N- epitaxial layer is formed on the surface of arsenic. The anode is made of a material such as molybdenum or aluminum. Using silicon dioxide (SiO2) to remove the electric field in the edge region and increase the pressure value of the tube. The H- type substrate has a very small on state resistance, and the doping concentration is 100% times higher than that of the N layer. The N+ cathode layer is formed on the base plate, which is to reduce the contact resistance of the cathode. By adjusting the structural parameters, the Schottky barrier is formed between the N and the anode metal, as shown in fig.. When in the Schottky barrier at both ends with forward bias (metal anode is connected to the positive pole, n-type substrate connected with the cathode of the power supply), Schottky barrier layer narrows, the resistance becomes smaller; on the contrary, if the Schottky

barrier at both ends and when a reverse bias voltage, Schottky barrier layer is wider, the resistance becomes large. In summary, Schottky rectifier structure principle and PN junction rectifier tube has great difference will usually PN junction rectifier tube called a junction rectifier tube, and the metal - semiconductor tube rectifier tube called Schottky rectifier tube, using planar silicon manufacturing process of Aluminum Silicon Schottky diode is also available, which not only can save precious metals, substantially reduce costs, but also improves the consistency of parameter.

特点

SBD的主要优点包括两个方面：肖特基二极管1）由于肖特基势垒高度低于PN结势垒高度，故其正向导通门限电压和正向压降都比PN结二极管低（约低0.2V）。2）由于SBD是一种多数载流子导电器件，不存在少数载流子寿命和反向恢复问题。SBD的反向恢复时间只是肖特基势垒电容的充、放电时间，完全不同于PN结二极管的反向恢复时间。由于SBD的反向恢复电荷非常少，故开关速度非常快，开关损耗也特别小，尤其适合于高频应用。但是，由于SBD的反向势垒较薄，并且在其表面极易发生击穿，所以反向击穿电压比较低。由于SBD比PN结二极管更容易受热击穿，反向漏电流比PN结二极

管大。

The main advantage of the SBD includes two aspects: Schottky diode 1) due to the Schottky barrier height is lower than the PN junction barrier height, so the positive guide through threshold voltage and forward voltage drop are than PN junction diode is low (about low 0.2V). 2) since SBD is a majority carrier conduction device, there is no minority carrier lifetime and reverse recovery problem. SBD reverse recovery time is only Schottky barrier capacitance of the charge and discharge time, completely different to the PN junction diode reverse recovery time. Because the reverse recovery charge of SBD is very few, so it is very fast and the switching loss is very small, especially for high frequency applications. However, due to the SBD's reverse barrier is thin, and its surface is very easy to breakdown, so the reverse breakdown voltage is relatively low. Because SBD is easier than the thermal breakdown of PN diode reverse

leakage current, high ratio of PN junction diode.

优点

SBD具有开关频率高和正向压降低等优点，但其反向击穿电压比较低，大多不高于60V，最高仅约100V，以致于限制了其应用范围。像在开关电源（SMPS）和功率因数校正（PFC）电路中功率开关器件的续流二极管、变压器次级用100V以上的高频整流二极管、RCD缓冲器电路中用600V～1.2kV的高速二极管以及PFC升压用600V二极管等，只有使用快速恢复外延二极管（FRED）和超快速恢复二极管（UFRD）。UFRD的反向恢复时间Trr也在20ns以上，根本不能满足像空间站等领域用1MHz～3MHz的SMPS需要。即使是硬开关为100kHz的SMPS，由于UFRD的导通损耗和开关损耗均较大，壳温很高，需用较大的散热器，从而使SMPS体积和重量增加，不符合小型化和轻薄化的发展趋势。因此，发展100V以上的高压SBD，一直是人们研究的课题和关注的热点。近几年，SBD已取得了突破性的进展，150V和200V的高压SBD已经上市，使用新型材料制作的超过1kV的SBD也研制成功，从而为其应用注入了新的生机与活力

SBD has the advantages of high switching frequency and low forward voltage, but the reverse breakdown voltage is low, mostly not higher than 60V, and the highest is only about 100V, which limits its application range. Like in the switching power supply (SMPS) and power factor correction (PFC) circuit in the power switch device, the power switch device, the transformer secondary with 100V above the high frequency rectifier diode, RCD buffer circuit with 1.2kV ~ 600V high speed diode and PFC boost 600V diode, etc., only use the fast recovery epitaxial diode (FRED) and ultra fast recovery diode (UFRD). UFRD reverse recovery time Trr is also more than 20ns, simply can not meet the needs of the 1MHz ~ SMPS 3MHz in the fields such as space station. Even hard switch for SMPS 100kHz, due to the conduction loss and switching losses of the UFRD, the shell is very high, with a larger heat sink, so as to increase the volume and weight of SMPS, does not meet the development trend of miniaturization and light. Therefore, the development of high

pressure 100V above SBD, has been a hot topic of research and concern. In recent years, SBD has made a breakthrough in the development of high voltage 150V 200V and SBD has been listed, the use of new materials production of more than SBD 1kV also developed, so as to its application to inject new vigor and vitality.

缺点

肖特基二极体最大的缺点是其反向偏压较低及反向漏电流偏大，像使用硅及金属为材料的肖特基二极体，其反向偏压额定耐压最高只到50V，而反向漏电流值为正温度特性，容易随着温度升高而急遽变大，实务设计上需注意其热失控的隐忧。

为了避免上述的问题，肖特基二极体实际使用时的反向偏压都会比其额定值小很多。不过肖特基二极体的技术也已有了进步，其反向偏压的额定值最大可以到200V。

Schottky diode the biggest drawback is the reverse bias voltage and low reverse leakage current is too large, as the use of silicon and metal

material of the Schottky diode, the reverse bias voltage rated pressure only to 50V, whereas the reverse leakage current value is positive temperature characteristics, easily with the temperature and abrupt change, design practice on the need to pay attention to the thermal runaway of worries.

In order to avoid the above problems, reverse biased Schottky diode in actual use will be smaller than its rated value. But Schottky diode technology also has improved, the reverse bias voltage rating can reach the maximum of 200V.

结构

金属导体内部有大量的导电电子。当金属与半导体接触（二者距离只有原子大小的数量级）时，金属的费米能级低于半导体的费米能级。在金属内部和半导体导带相对应的分能级上，电子密度小于半导体导带的电子密度。因此，在二者接触后，电子会从半导体向金属扩散，从而使金属带上负电荷，半导体带正电荷。由于金属是理想的导体，负电荷只分布在表面为原子大小的一个薄层之内。而对于N型半导体来说，失去电子的施主杂质原子成为正离子，则分布在较大的厚度之中。电子从半导体向金属扩散运动的结果，形成空间电荷区、自建电场和势垒，并且耗尽层只在N型半导体一边（势垒区全部落在半导体一侧）。势垒区中自建电场方向由N型区指向金属，随热电子发射自建场增加，与扩散电流方向相反的漂移电流增大，最终达到动态平衡，在金属与半导体之间形成一个接触势垒，这就是肖特基势垒。

在外加电压为零时，电子的扩散电流与反向的漂移电流相等，达到动态平衡。在加正向偏压（即金属加正电压，半导体加负电压）时，自建场削弱，半导体一侧势垒降低，于是形成从金属到半导体的正向电流。当加反向偏压时，自建场增强，势垒高度增加，形成由半导体到金属的较小反向电流。因此，SBD与PN结二极管一样，是一种具有单向导电性的非线。

There are a large number of conducting electrons inside the metal conductor. When the metal is in contact with the semiconductor (the two is only a small number of atomic size), the Fermi level of

the metal is lower than the Fermi level of the semiconductor. The electron density of the electron density is less than the electron density of the semiconductor conduction band at the corresponding level of the metal inner and the semiconductor conduction band. Therefore, after the two contact, the electrons from the semiconductor to metal diffusion, so that the metal with a negative charge, a positive charge of the semiconductor. Because the metal is an ideal conductor, the negative charge is only distributed in the surface of a thin layer of atomic size. For N type semiconductor, lost electron donor impurity atoms become positive ions, are located in the greater thickness. Electrons from the semiconductor to metal diffusion movement of the results, the formation of space charge region, self electric field and barrier, and depletion layer only on the side of the N type semiconductor (barrier area all fell on the semiconductor side). In the barrier region, the electric field direction of the electric field is from the N zone to the metal, with the increase of the thermal electron emission, the drift current increases with the diffusion current direction, and finally reaches the dynamic balance, and forms a contact barrier between the metal and the semiconductor. This is the Schottky barrier.

When the applied voltage is zero, the diffusion current of the electron is equal to that of the reverse drift current, which can reach the dynamic balance. In addition to the forward bias (i.e., when the metal is positive, the negative voltage of the semiconductor), the self built field is weakened, and the semiconductor side barrier is reduced, and the forward current is formed from metal to semiconductor. When the reverse bias voltage is added, the self built field is enhanced, and the barrier height is increased, which is formed from the semiconductor to metal. Therefore, SBD and PN junction diode, is a non line with unidirectional conductivity.

应用

SBD的结构及特点使其适合于在低压、大电流输出场合用作高频整流，在非常高的频率下（如X波段、C波段、S波段和Ku波段）用于检波和混频，在高速逻辑电路中用作箝位。在IC中也常使用SBD，像SBD?TTL集成电路早已成为TTL电路的主流，在高速计算机中被广泛采用。

除了普通PN结二极管的特性参数之外，用于检波和混频的SBD电气参数还包括中频阻抗（指SBD施加额定本振功率时对指定中频所呈现的阻抗，一般在200Ω～600Ω之间）、电压驻波比（一般≤2）和噪声系数等。

The structure and characteristics of SBD to fit in in the field of low voltage, high current output combination for high frequency rectifier, at very high frequencies (X-band, C-band, S band and Ku band) for detection and mixing, in high speed logic circuit as clamping. IC is also often used in SBD, such as SBD TTL integrated circuits have become the mainstream of the TTL circuit, the high speed computer is widely used.

In addition to ordinary PN diode parameters for detector and mixer SBD electrical parameters including impedance of middle frequency impedance (SBD rated Lo power is applied to specify if present, general between 200 ohms to 600 ohms), voltage standing wave ratio (VSWR) (generally less than or equal to 2) and noise coefficient.

作用

作用：二极管的主要特性是单向导电性，也就是在正向电压的作用下，导通电阻很小；而在反向电压作用下导通电阻极大或无穷大。正因为二极管具有上述特性，无绳电话机中常把它用在整流、隔离、稳压、极性保护、编码控制、调频调制和静噪等电路中。电话机里使用的晶体二极管按作用可分为：整流二极管（如1N4004）、隔离二极管（如1N4148）、肖特基二极管（如BAT85）、发光二极管、稳压二极管等。

Role: the main characteristics of the diode is a one-way conductivity, that is, the role of the forward voltage, the resistance is very small;

And in the reverse voltage, the resistance is great or infinite. Because of having the characteristics of diode, the cordless telephone often

To put it in the rectification, isolation, voltage, polarity protection, encoding control, frequency modulation and squelch circuit.

The use of crystal diode in the telephone can be divided into: rectifier diode (e.g.1N4004(for example,)1N4148Schottky diode (e.g.BAT85), light emitting diodes, voltage regulators, etc..

肖特基二极管的结构肖特基二极管在结构原理上与PN结二极管有很大区别，它的内部是由阳极金属（用钼或铝等材料制成的阻挡层）、二氧化硅（SiO2）电场消除材料、N-外延层（砷材料）、N型硅基片、N+阴极层及阴极金属等构成，如图4-44所示。在N型基片和阳极金属之间形成肖特基势垒。当在肖特基势垒两端加上正向偏压（阳极金属接电源正极，N型基片接电源负极）时，肖特基势垒层变窄，其内阻变小；反之，若在肖特基势垒两端加上反向偏压时，肖特基势垒层则变宽，

其内阻变大。

Schottky diode structure Schottky diode in the structure principle PN There is a big difference in the junction diode, which is made of the anode metal (molybdenum or Barrier layer made of aluminum and other materials), silica (SiO2) electric field eliminating material,N- Epitaxial layer (arsenic material),N Type silicon substrate,N+ Cathode layer and cathode metal,Figure 4-44 Shown. In N The Schottky barrier is formed between the substrate and the anode metal. Positive bias at both ends of the Schottky barrier (positive electrode,N Type Substrate is connected with a power supply anode), Schottky barrier layer narrows, the resistance becomes smaller; on the contrary, if the Schottky barrier at both ends and when a reverse bias voltage, Schottky barrier layer wider,

The larger resistance.