肖特基二极管

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

-

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

< br>，

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

< br>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

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

< br>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

（

）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

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

SB D

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