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半导体电阻率的温度依赖性

关键要点

  • 随着温度的升高,金属的电阻率会增加,从而使其具有正电阻系数。

  • 半导体具有负电阻系数。

  • 外部半导体的电阻率大于内在的半导体。

半导体制造

半导体电阻率的温度依赖性在其在电子中的应用中起着重要作用

电导率描述了电流可以通过材料的易于性,并且是材料的重要参数。导体是允许电流通过它们的材料。阻止电流流量的那些被称为绝缘体。当流过它们的电流作为相对参数时,有些材料落在导体和绝缘体之间。这样的材料称为半导体。

In all these materials, the current flow can be directly related to theconductivity of the material,这是电阻率的倒数。电阻率是物质属性,它是温度依赖性。半导体电阻率的温度依赖性在其在电子中的应用中起着重要作用。In this article, we will explore why this is.

什么是电阻率?

Resistivity is an intrinsic property of a material. It is a constant for在给定温度下的材料。The resistivity of a material can be defined as the resistance of the material of unit cross-sectional area and unit length. The resistivity of a material is independent of its length and area.

r = la

材料的电阻和电阻率之间的关系是:

注意,R是阻力,is the resistivity of the material, l is the length, and A is the cross-sectional area of the material. The unit of resistivity is ohm meter.

The conductivity is the reciprocal of resistivity. When the resistivity of a material is high, then its conductivity is very low, and vice versa. Considering this relationship, it can be said that the resistivity of metals or conductors is very low. Arranging the materials in the ascending order of resistivity, the order is conductors, semiconductors, and insulators.

接下来,我们将探讨温度如何影响电阻率。

The Temperature Dependence of Resistivity

材料的电阻率取决于温度。对于导体,半导体和绝缘体,电阻率的温度依赖性不同。让我们讨论在讨论半导体之前,电阻率在导体和绝缘体中如何变化。

导体

In conductors, as temperature increases, the atoms start vibrating heavily, leading to the collision of free electrons and other electrons. This collision causes a loss of energy from free electrons, which are responsible for the current flow. The reduction in the movement, or drift velocity, of the electrons due to energy drain increases the resistivity of the conductors, especially metals. As the temperature increases, the resistivity of the metal increases as well, giving it a positive temperature coefficient of resistance. At high temperatures, the conductor resistivity increases and conductivity decreases.

绝缘子

绝缘体随温度升高而转移到传导区。绝缘子的电阻率随温度而降低,导致电导率增加。绝缘子表现出负电阻系数。

接下来,我们将探索半导体电阻率的温度依赖性。

半导体电阻率的温度依赖性

在半导体中,随着温度的升高,导带和价带之间的能量差距减小。半导体材料中的价电子获得能量,以打破共价键并在高温下跳到传导带。这会在semiconductor at high temperatures。较高的电荷载体降低了半导体的电阻率。随着半导体的电阻率随温度的升高而降低,它变得更加导电。半导体在高温下表现出极好的电导率。

下图显示了半导体中电阻率和温度之间的关系。半导体具有负电阻系数。该特性用于在电子中应用半导体。当施加外部电压时,半导体晶体的温度会增加,从而增加了热产生的载体的密度。产生了更多的电子孔对,从而使电流易于流过半导体。

Resistivity vs. temperature graph

Resistivity vs. temperature in semiconductors

A semiconductor’s performance is enhanced by doping it with donor or acceptor impurities. Such semiconductors are called extrinsic semiconductors. The resistivity of extrinsic semiconductors is greater than intrinsic (undoped or pure) semiconductors.

The temperature dependence of the resistivity of semiconductors is greatly beneficial; the semiconductor electronics we use today are possible only due to the negative temperature coefficient of resistance. Cadence offers a suite of design and analysis tools to help build solid-state electronic circuits.

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