集成电路(外文翻译)

学号：10034020321

毕业设计外文翻译

学院 计算机与电子信息学院 专业 电气工程及其自动化 班级 电气10-3班 学生 赖景来 指导教师 罗如山（讲师） 设计时间 2014年03月24日至 2014年06月27日

Integrated circuit (IC)

Introducion

Integrated circuit also called microelectronic circuit or chip an assembly of electronic components, fabricated as a single unit, in which miniaturized active devices (e.g., transistors and diodes) and passive devices (e.g., capacitors and resistors) and their interconnections are built up on a thin substrate of semiconductor material (typically silicon). The resulting circuit is thus a small monolithic “chip,” which may be as small as a few square centimetres or only a few square millimetres. The individual circuit components are generally microscopic in size.

Integrated circuits have their origin in the invention of the transistor in 1947 by William B. Shockley and his team at the American Telephone and Telegraph Company's Bell Laboratories. Shockley's team (including John Bardeen and Walter H. Brattain) found that, under the right circumstances, electrons would form a barrier at the surface of certain crystals, and they learned to control the flow of electricity through the crystal by manipulating this barrier. Controlling electron flow through a crystal allowed the team to create a device that could perform certain electrical operations, such as signal amplification, that were previously done by vacuum tubes. They named this device a transistor, from a combination of the words transfer and resistor (see photograph). The study of methods of creating electronic devices using solid materials became known as solid-state electronics. Solid-state devices proved to be much sturdier, easier to work with, more reliable, much smaller, and less expensive than vacuum tubes.

Using the same principles and materials, engineers soon learned to create other electrical components, such as resistors and capacitors. Now that electrical devices could be made so small, the largest part of a circuit was the awkward wiring between the

devices.

In 1958 Jack Kilby of Texas Instruments, Inc., and Robert Noyce of Fairchild Semiconductor Corporation independently thought of a way to reduce circuit size further. They laid very thin paths of metal (usually aluminum or copper) directly on the same piece of material as their devices. These small paths acted as wires. With this technique an entire circuit could be “integrated” on a single piece of solid material and an integrated circuit (IC) thus created. ICs can contain hundreds of thousands of individual transistors on a single piece of material the size of a pea. Working with that many vacuum tubes would have been unrealistically awkward and expensive. The invention of the integrated circuit made technologies of the Information Age feasible. ICs are now used extensively in all walks of life, from cars to toasters to amusement park rides.

Basic IC types

Analog versus digital circuits

Analog, or linear, circuits typically use only a few components and are thus some of the simplest types of ICs. Generally, analog circuits are connected to devices that collect signals from the environment or send signals back to the environment. For example, a microphone converts fluctuating vocal sounds into an electrical signal of varying voltage. An analog circuit then modifies the signal in some useful way—such as amplifying it or filtering it of undesirable noise. Such a signal might then be fed back to a loudspeaker, which would reproduce the tones originally picked up by the microphone.

Another typical use for an analog circuit is to control some device in response to continual changes in the environment. For example, a temperature sensor sends a varying signal to a thermostat, which can be programmed to turn an air conditioner, heater, or oven on and off once the signal has reached a certain value.

A digital circuit, on the other hand, is designed to accept

only voltages of specific given values. A circuit that uses only two states is known as a binary circuit. Circuit design with binary quantities, “on” and “off” representing 1 and 0 (i.e., true and false), uses the logic of Boolean algebra. The three basic logic functions—NOT, AND, and OR—together with their truth tables are given in the figure. (Arithmetic is also performed in the binary number system employing Boolean algebra.) These basic elements are combined in the design of ICs for digital computers and associated devices to perform the desired functions.

Microprocessor circuits

Microprocessors are the most complicated ICs. They are composed of millions of transistors that have been configured as thousands of individual digital circuits, each of which performs some specific logic function. A microprocessor is built entirely of these logic circuits synchronized to each other.

Just like a marching band, the circuits perform their logic function only on direction by the bandmaster. The bandmaster in a microprocessor, so to speak, is called the clock. The clock is a signal that quickly alternates between two logic states. Every time the clock changes state, every logic circuit in the microprocessor does something. Calculations can be made very quickly, depending on the speed (“clock frequency”) of the microprocessor.

Microprocessors contain some circuits, known as registers, that store information. Registers are predetermined memory locations. Each processor has many different types of registers. Permanent registers are used to store the preprogrammed instructions required for various operations (such as addition and multiplication). Temporary registers store numbers that are to be operated on and also the result. Other examples of registers include the “program counter,” the “stack pointer,” and the “address” register.

Microprocessors can perform millions of operations per second

on data. In addition to computers, microprocessors are common in video game systems, televisions, cameras, and automobiles.

Memory circuits

Microprocessors typically have to store more data than can be held in a few registers. This additional information is relocated to special memory circuits. Memory is composed of dense arrays of parallel circuits that use their voltage states to store information. Memory also stores the temporary sequence of instructions, or program, for the microprocessor. Manufacturers continually strive to reduce the size of memory circuits—to increase capability without increasing space. In addition, smaller components typically use less power, operate more efficiently, and cost less to manufacture.

Digital signal processors

A signal is an analog waveform—anything in the environment that can be captured electronically. A digital signal is an analog waveform that has been converted into a series of binary numbers for quick manipulation. As the name implies, a digital signal processor (DSP) processes signals digitally, as patterns of 1s and 0s. For instance, using an analog-to-digital converter, commonly called an A-to-D or A/D converter, a recording of someone's voice can be converted into digital 1s and 0s. The digital representation of the voice can then be modified by a DSP using complex mathematical formulas. For example, the DSP algorithm in the circuit may be configured to recognize gaps between spoken words as background noise and digitally remove ambient noise from the waveform. Finally, the processed signal can be converted back (by a D/A converter) into an analog signal for listening. Digital processing can filter out background noise so fast that there is no discernible delay and the signal appears to be heard in “real time.” For instance, such processing enables “live” television broadcasts to focus on a quarterback's signals in an American

gridiron football game. DSPs are also used to produce digital effects on live television. For example, the yellow marker lines displayed during the football game are not really on the field; a DSP adds the lines after the cameras shoot the picture but before it is broadcast. Similarly, some of the advertisements seen on stadium fences and billboards during televised sporting events are not really there.

Application-specific ICs

An application-specific IC (ASIC) can be either a digital or an analog circuit. As their name implies, ASICs are not reconfigurable; they perform only one specific function. For example, a speed controller IC for a remote control car is hard-wired to do one job and could never become a microprocessor. An ASIC does not contain any ability to follow alternate instructions.

Radio-frequency ICs

Radio-frequency ICs (RFICs) are rapidly gaining importance in cellular telephones and pagers. RFICs are analog circuits that usually run in the frequency range of 900 MHz to 2.4 GHz (900 million hertz to 2.4 billion hertz). They are usually thought of as ASICs even though some may be configurable for several similar applications. Most semiconductor circuits that operate above 500 MHz cause the electronic components and their connecting paths to interfere with each other in unusual ways. Engineers must use special design techniques to deal with the physics of high-frequency microelectronic interactions.

Microwave monolithic ICs

A special type of RFIC is known as a microwave monolithic IC (MMIC). These circuits run in the 2.4- to 20-GHz range, or

microwave frequencies, and are used in radar systems, in satellite communications, and as power amplifiers for cellular telephones.

Just as sound travels faster through water than through air, electron velocity is different through each type of semiconductor material. Silicon offers too much resistance for microwave-frequency circuits, and so the compound gallium arsenide (GaAs) is often used for MMICs. Unfortunately, GaAs is mechanically much less sound than silicon. It breaks easily, so GaAs wafers are usually much more expensive to build than silicon wafers.

Basic semiconductor design

Any material can be classified as one of three types: conductor, insulator, or semiconductor. A conductor (such as copper or salt water) can easily conduct electricity because it has an abundance of free electrons. An insulator (such as ceramic or dry air) conducts electricity very poorly because it has few or no free electrons. A semiconductor (such as silicon or gallium arsenide) is somewhere between a conductor and an insulator. It is capable of conducting some electricity, but not much.

Basic semiconductor design

Doping silicon

Most ICs are made of silicon, which is abundant in ordinary beach sand. Pure crystalline silicon, as with other semiconducting materials, has a very high resistance to electrical current at normal room temperature. However, with the addition of certain impurities, known as dopants, the silicon can be made to conduct usable currents. In particular, the doped silicon can be used as a switch, turning current off and on as desired.

The process of introducing impurities is known as doping or implantation. Depending on a dopant's atomic structure, the result of implantation will be either an n-type (negative) or a p-type (positive) semiconductor. An n-type semiconductor results from

implanting dopant atoms that have more electrons in their outer (bonding) shell than silicon, as shown in the figure. The resulting semiconductor crystal contains excess, or free, electrons that are available for conducting current. A p-type semiconductor results from implanting dopant atoms that have fewer electrons in their outer shell than silicon. The resulting crystal contains “holes” in its bonding structure where electrons would normally be located. In essence, such holes can move through the crystal conducting positive charges.

Basic semiconductor design

The p-n junction

A p-type or an n-type semiconductor is not very useful on its own. However, joining these opposite materials creates what is called a p-n junction. A p-n junction forms a barrier to conduction between the materials. Although the electrons in the n-type material are attracted to the holes in the p-type material, the electrons are not normally energetic enough to overcome the intervening barrier. However, if additional energy is provided to the electrons in the n-type material, they will be capable of crossing the barrier into the p-type material—and current will flow. This additional energy can be supplied by applying a positive voltage to the p-type material,as shown in the figure. The negatively charged electrons will then be highly attracted to the positive voltage across the junction.

A p-n junction that conducts electricity when energy is added to the n material is called forward-biased because the electrons move forward into the holes. If voltage is applied in the opposite direction—a positive voltage connected to the n side of the junction—no current will flow. The electrons in the n material will still be attracted to the positive voltage, but the voltage will now be on the same side of the barrier as the electrons. In this state a junction is said to be reverse-biased. Since p-n junctions conduct electricity in only one direction, they are a type of diode. Diodes are essential building blocks of

semiconductor switches.

Basic semiconductor design

Field-effect transistors

Bringing a negative voltage close to the centre of a long strip of n-type material will repel nearby electrons in the material and thus form holes—that is, transform some of the strip in the middle to p-type material. This change in polarity utilizing an electric field gives the field-effect transistor its name. (See animation.) While the voltage is being applied, there will exist two p-n junctions along the strip, from n to p and then from p back to n. One of the two junctions will always be reverse-biased. Since reverse-biased junctions cannot conduct, current cannot flow through the strip. The field effect can be used to create a switch (transistor) to turn current off and on, simply by applying and removing a small voltage nearby in order to create or destroy reverse-biased diodes in the material. A transistor created by using the field effect is called a field-effect transistor (FET).

The location where the voltage is applied is known as a gate. The gate is separated from the transistor strip by a thin layer of insulation to prevent it from short-circuiting the flow of electrons through the semiconductor from an input (source) electrode to an output (drain) electrode. Similarly, a switch can be made by placing a positive gate voltage near a strip of p-type material. A positive voltage attracts electrons and thus forms a region of n within a strip of p. This again creates two p-n junctions, or diodes. As before, one of the diodes will always be reverse-biased and will stop current from flowing. FETs are good for building logic circuits because they require only a small current during switching. No current is required for holding the transistor in an on or off state; a voltage will maintain the state. This type of switching helps preserve battery life. A field-effect transistor is called unipolar (from “one polarity”) because the main conduction method is either holes or electrons, not both.

Basic semiconductor design

Enhancement mode FETs

There are two basic types of field-effect transistors. The type described previously is a depletion mode FET, since a region is depleted of its natural charge. The field effect can also be used to create what is called an enhancement mode FET by enhancing a region to appear similar to its surrounding regions.

An n-type enhancement mode FET is made from two regions of n-type material separated by a small region of p. As this FET naturally contains two p-n junctions—two diodes—it is normally switched off. However, when a positive voltage is placed on the gate, the voltage attracts electrons and creates n-type material in the middle region, filling the gap that was previously p-type material, as shown in the animation. The gate voltage thus creates a continuous region of n across the entire strip, allowing current to flow from one side to the other. This turns the transistor on. Similarly, a p-type enhancement mode FET can be made from two regions of p-type material separated by a small region of n. The gate voltage required for turning on this transistor is negative. Enhancement mode FETs switch faster than depletion mode FETs because they require a change only near the surface under the gate, rather than all the way through the material, as shown in the figure.

Basic semiconductor design

Complementary metal-oxide semiconductors

Recall that placing a positive voltage at the gate of an n-type enhanced mode FET will turn the switch on. Placing the same voltage at the gate of a p-type enhanced mode FET will turn the switch off. Likewise, placing a negative voltage at the gate will turn the n-type off and the p-type on. These FETs always respond in opposite, or complementary, fashion to a given gate voltage. Thus, if the gates of an n-type and a p-type FET are connected, any voltage applied to the common gate will operate the complementary pair,

turning one on and leaving the other off. A semiconductor that pairs n- and p-type transistors this way is called a complementary metal-oxide semiconductor (CMOS). Because complementary transistor pairs can quickly switch between two logic states, CMOSs are very useful in logic circuits. In particular, because only one circuit is on at any time, CMOSs require less power and are often used for battery-powered devices, such as in digital cameras, and for the special memory that holds the date, time, and system parameters in personal computers.

Basic semiconductor design

Bipolar transistors

Bipolar transistors simultaneously use holes and electrons to conduct, hence their name (from “two polarities”). Like FETs, bipolar transistors contain p- and n-type materials configured in input, middle, and output regions. In bipolar transistors, however, these regions are referred to as the emitter, the base, and the collector. Instead of relying, as FETs do, on a secondary voltage source to change the polarity beneath the gate (the field effect), bipolar transistors use a secondary voltage source to provide enough energy for electrons to punch through the reverse-biased base-collector junction (see figure). As the electrons are energized, they jump into the collector and complete the circuit. Note that even with highly energetic electrons, the middle section of p-type material must be extremely thin for the electrons to pass through both junctions.

Designing ICs

All ICs use the same basic principles of voltage (V), current (I), and resistance (R). In particular, equations based on Ohm's law, V = IR, determine many circuit design choices. Design engineers must also be familiar with the properties of various electronic components needed for different applications.

Designing ICs

Analog design

As mentioned earlier, an analog circuit takes an infinitely variable real-world voltage or current and modifies it in some useful way. The signal might be amplified, compared with another signal, mixed with other signals, separated from other signals, examined for value, or otherwise manipulated. For the design of this type of circuit, the choice of every individual component, size, placement, and connection is crucial. Unique decisions abound—for instance, whether one connection should be slightly wider than another connection, whether one resistor should be oriented parallel or perpendicular to another, or whether one wire can lie over the top of another. Every small detail affects the final performance of the end product. When integrated circuits were much simpler, component values could be calculated by hand. For instance, a specific amplification value (gain) of an amplifier could typically be calculated from the ratio of two specific resistors. The current in the circuit could then be determined, using the resistor value required for the amplifier gain and the supply voltage used. As designs became more complex, laboratory measurements were used to characterize the devices. Engineers drew graphs of device characteristics across several variables and then referred to those graphs as they needed information for their calculations. As scientists improved their characterization of the intricate physics of each device, they developed complex equations that took into account subtle effects that were not apparent from coarse laboratory measurements. For example, a transistor works very differently at different frequencies, sizes, orientations, and placements. In particular, scientists found parasitic components (unwanted effects, usually resistance and capacitance) that are inherent in the way the devices are built.

Designing ICs

Digital design

Since digital circuits involve millions of times as many components as analog circuits, much of the design work is done by copying and reusing the same circuit functions, especially by using digital design software that contains libraries of prestructured circuit components. The components available in such a library are of similar height, contain contact points in predefined locations, and have other rigid conformities so that they fit together regardless of how the computer configures a layout. While SPICE is perfectly adequate for analyzing analog circuits, with equations that describe individual components, the complexity of digital circuits requires a less-detailed approach. Therefore, digital analysis software ignores individual components for mathematical models of entire preconfigured circuit blocks (or logic functions).

Whether analog or digital circuitry is used depends on the function of a circuit. The design and layout of analog circuits are more demanding of teamwork, time, innovation, and experience, particularly as circuit frequencies get higher, though skilled digital designers and layout engineers can be of great benefit in overseeing an automated process as well. Digital design emphasizes different skills from analog design.

集成电路（IC）

集成电路也称为微电子电路或芯片的电子元件，作为一个单元，其中微型有源器件（如晶体管和二极管）和无源器件（例如，电容器和电阻器）和他们的互连是建立在制造薄基板的半导体材料（通常是硅）。从而产生电路是一个小铁板和一块“芯片”，这可能只有几平方厘米的小或只有几平方毫米，这就是一般大小的微观个人的电路元件。

集成电路是他们在1947年由William B. Shockley和他的团队在美国电话电报公司的贝尔实验室发明的晶体管。肖克利的团队（包括John Bardeen和Walter H.的布拉坦的）发现，在正常情况下，电子会在某些晶体表面形成的障碍，他们学会了控制流动的电力通过晶体。控制晶体的电子流通过允许团队创建一个设备，可以进行一定的电气操作，如信号放大，真空管，以前他们命名这种设备为晶体管，由一个组合的传输和电阻组成设备（见照片）。创造电子设备，使用固体材料的方法的研究成品被称为固态电子。固态装置被证明比其他装置更坚固，更容易使用，更可靠，更小，但是它比真空管昂贵。

使用相同的原则和材料，工程师很快就学会了创建其他的电器元件，

如电阻和电容，但电路的最大挑战是设备之间的接线。 1958年，由于杰克·基尔比，德州仪器公司和半导体公司的罗伯特·诺伊斯创立了思想的方法，从而进一步减少电路的尺寸。这个方法奠定

了金属的路径（通常为铝或铜），那就是直接用一块材料作为其设备，以这些小的路径作为电线。使整个电路可以以坚实的物质单件“一体化”的技术和集成电路（IC）为创造基础。芯片可以包含成千上万如豌豆大小的单个晶体管的材料单件。本来，许多真空管是昂贵的，可是集成电路的发明使信息时代的技术变得可行。集成电路现在广泛应用在各行各业，从汽车到游乐园的游乐设施再到家庭用的烤面包机等等。

基本IC类型

模拟与数字电路

模拟，或线性电路通常只使用几个组件，这就是一些IC的简单类型。一般来说，模拟电路连接到设备时，都会从环境中收集信号或发出信号。例如，一个麦克风转换成电信号的不同电压波动的声音。模拟电路就会修改一些有用的方式，如放大或过滤不良噪音的信号。这样一个信号，可能会被反馈到扬声器，然后将重现最初拿起麦克风的音。

模拟电路的另一个典型的用途是在回应不断变化的环境，然后控制某些设备。例如，一个温度传感器发送到一个恒温变化的信号，它可以编程来打开和关闭空调，热水器，或烤箱一旦收到信号就会体现其功能。

数字电路，旨在接受只有特定的定值电压被称为二进制电路的电路。使用时只有两种状态，电路设计与二进制数量，“开”和“关”代表1和0（即true和false），用的事代数的逻辑。图中给出的三个基本逻辑功能，不、与、或，连同其真值表。（算术也采用二进制数布尔代数系统中执行。）这些基本元素相结合，在集成电路设计中为数码电脑和相关设备，以执行所需的功能。 微处理器电路

微处理器是最复杂的集成电路。它们是由数百万个晶体管，成千上万的个人数字电路组成，其中每个执行一些特定的逻辑功能配置。微处理器完全是建立在这些逻辑电路相互同步的基础上的。就像一个军乐队，电路执行方向由乐队指挥他们的逻辑功能。，可以这么说，在微处理器的乐队指挥被称为时钟。时钟是一个信号，两个逻辑状态之间迅速交替。

每次时钟状态发生变化，每一个逻辑电路，微处理器做一些事情。根据微处理器的速度（“时钟频率”），可以计算得非常快。微处理器中包含一些电路，被称为寄存器，用来存储信息，即寄存器预定的内存位置。每个处理器都有许多不同类型的寄存器。常驻寄存器用来存储预先设定的指令所需的各种操作（如加法和乘法）。临时寄存器存储的数字将被作为操作结果。寄存器的其他例子包括“程序计数器”，“堆栈指针”和“地址”注册。

微处理器可以执行每秒的数据高达百万。除了电脑，微处理器是常见的视频游戏系统。

存储器电路

微处理器通常可以存储很多的数据。这些额外的信息迁移到特殊的记忆体电路中。内存组成的并联电路使用的电压状态来存储信息的密集阵列。记忆存储指令或程序的临时序列，称作微处理器。制造商不断努力，以减少的内存大小的电路，从而增加空间的能力。此外，较小的组件通常使用更少的功率，更有效地运作，并可以减少生产成本。数字信号处理器

一个信号就是模拟波形在任何一个电子环境可以被捕捉的信号。数字信号是模拟波形，已转换成一系列二进制数字。顾名思义，数字信号处理器（DSP）处理信号的数字，1s和0s模式。例如，使用一个模拟 - 数字转换器，俗称A至D或A / D转换器，一个人的声音的录音可以转换成数字1和0。通过使用复杂的数学公式DSP的数字代表的声音，然后可以修改。例如，电路中的DSP算法，可配置承认所说的话作为背景噪声和数字消除环境噪声的波形之间的差距。最后，处理后的信号可以转换回（由D / A转换）到模拟信号的听觉。数字信号处理可以过滤背景噪音很快，举例来说，这样的处理使“现场”电视节目的广播把重点放在1个四分卫的信号。DSP还用于生产数字电视直播的影响。例如，在足球比赛中显示黄色标记线是不是真领域的DSP增加了线后相机拍摄的图片。同样，就如体育场围栏和电视体育赛事期间的广告牌上看到一些广

告是不是真的。

应用专用集成电路

一个特定应用集成电路（ASIC），可以是一个数字或模拟电路。顾名思义， ASIC是不是重构;他们只执行一个特定的功能。例如，一个远程控制汽车的速度控制器IC是硬接线做的一个工作，不可能成为一个微处理器。ASIC中不包含任何能够遵循替代的指示。

射频集成电路

射频集成电路（RFIC的）正在迅速移动电话和传呼机的重要性。RFIC的是，通常在900兆赫的频率范围内运行至2.4千兆赫（900百万赫兹到2.4亿赫兹）的模拟电路。他们通常认为，即使作为ASIC的一些可配置几个类似的应用。大多数半导体电路500兆赫以上操作造成的电子元件和连接路径，在不寻常的方式互相干扰。工程师必须使用特殊的设计技术与高频微电子相互作用的物理处理。微波单片集成电路

一个特殊类型的射频微波单片集成电路（MMIC），被称为。这些电路运行在2.4到20 GHz范围内，或微波频率，并在雷达系统，卫星通信，使用，以及用于蜂窝电话功率放大器。

一样的声音通过水传播的速度比通过空气通过每种类型的半导体材料，电子的传播速度是不同的。硅微波高频电路提供了太多的阻力，所以常常使用MMIC的化合物砷化镓（GaAs）。不幸的是，砷化镓比硅机械少得多。它容易打破，所以砷化镓晶圆通常比硅片建立更加昂贵。

基本的半导体设计

任何材料可分为三种类型之一：导体，绝缘体或半导体。导体（如铜或咸水），可以很容易地进行发电，因为它有大量的自由电子。绝缘体（如陶瓷或干燥的空气）的导电性很差，因为它有很少或根本没有自由电子。半导体（如硅或砷化镓），是介于导体和绝缘体。它是能够发出一些电力，但数量不多。基本的半导体设计掺杂硅

大多数集成电路芯片,如纯净的晶体硅，与其他半导体材料都可以掺杂。然而，与某些杂质，掺杂已知此外，硅可以进行电流测试。，尤其是掺杂硅可以用来作为一个开关，转向当前打开和关闭的需要，引入杂质的过程被称为掺杂或注入。

根据掺杂剂的原子结构，植入的结果将是一个n型（负）或p型（正）半导体。从植入有更多的电子在其外层（粘接）外壳比硅的掺杂原子的n型半导体的结果，图中所示。半导体晶体含有多余的，或自由电子传导电流。从植入，在其外壳比硅少的电子掺杂原子的p型半导体。由此产生的晶体包含在其粘接结构通常位于电子的“洞”。在本质上，这些孔可以进行正电荷的晶体移动。

p型或n型半导体参加这些相反的材料创建被称为pn结。一个PN结形成的材料之间的传导障碍。虽然在n型材料中的电子被吸引在p型材料的孔，电子不正常能量足以克服干预屏障。然而，如果在n型材料的电子提供额外的能量，他们将能够穿越屏障进入p型材料和电流会流入。这种额外的能量，可提供的p型材料施加一个正电压，如下图所示。电子带负电荷，然后将高度吸引到整个路口的正电压。

导电时能量被添加到N材料的PN结正向偏置，被称为电子移动。如果电压施加相反方向的正电压连接到N侧的交界处将没有流入。N材料的电子仍然会被吸引到正电压，但现在同方作为电子屏障的电压。在这种状态下一个路口说是反向偏置。由于pn结只在一个方向进行发电，他们是一个类型的二极管。二极管是半导体开关的重要基石。基本的半导体设计场效应晶体管

带来的负电压接近中心的n型材料的长条形，将被排斥在附近的电子材料，从而形式是，一些转化的中间地带的p型材料。这利用电场极性变化给场效应晶体管，它的名字。（看动画）当电压被应用，将沿条存在两个pn结，从n到p，然后从p到n。两路口将永远是反向偏置。由于不能进行反向偏置结，电流不能流过条。可以用来创建一个开关（晶

基本的半导体设计p-n结

体管）把当前的关闭，只需申请和消除附近的一个小的电压，以创建或销毁材料中的反向偏置二极管，场效应。使用场效应晶体管被称为场效应晶体管（FET）。被称为门的位置，施加电压。门被分离由薄绝缘层，以防止短路输入（源）电极的电子流通过半导体输出（漏）电极从晶体管条。同样，一个开关，可以由p型材料带附近放置了积极的栅极电压。一个正电压吸引电子，从而形成n个区域内的p带。这再次创造了两个P-N结，或二极管。如前所述，一个二极管将永远是反向偏置，将停止电流。场效应管是构建逻辑电路开关期间，因为他们需要的只是一个很小的电流。目前没有需要举行晶体管的开启或关闭状态;电压将保持这种状态。这种类型的交换，有助于延长电池寿命。一个场效应晶体管被称为单极性（从“一极”），因为主要的传导方法是要么孔或电子，不是两个都有。

基本的半导体设计 增强型场效应管

有两个基本类型的场效应晶体管。前面所述的类型是耗尽型场效应管，因为一个地区的自然电荷耗尽。场效应也可以用来创建被称为增强型场效应管，提高一个地区及其周边地区出现类似。

N型增强型场效应管是由n型材料由小p的地区分隔两个地区。由于这FET自然包含两个pn路口 ，它通常被关掉。然而，在门上放置一个正电压时，电压吸引电子，并建立在n型材料，填补中部地区的差距，以前是p型材料，如动画中所示。栅极电压，从而造成整个带n个连续的区域，使电流从一方流向其他。这将晶体管。同样，一个P-型增强型场效应管，可从两个地区小区域的n分隔的p型材料。打开这种晶体管的栅极电压为负。增强型场效应晶体管切换速度比耗尽型场效应管，因为他们需要根据门的变化只是表面附近的，而不是通过材料的方式。

基本的半导体设计

互补金属氧化物半导体

记得，在n型增强模式FET的栅极正电压将打开开关。名次相同的电压，在p型增强模式FET的栅极，将关闭开关。同样，在门口放置一个负电压会变成n型的关闭和p型。这些场效应管总是在对面的回应，或一个给定的栅极电压的互补性，时尚。因此，如果n型和p型FET的闸相连，任何电压适用于普通门，将经营的互补配对，转向一个离开的其他关闭。一对n型和p型晶体管，这种方式被称为互补金属氧化物半导体（CMOS）半导体。由于互补晶体管对两个逻辑状态之间可以快速切换，CMOSs是非常有用的逻辑电路。特别，因为只有一个电路是在任何时间，CMOSs需要较少的功率，并经常用于电池供电的设备，如数码相机，还有就是如个人电脑所特有的日期，时间和系统参数的特殊内存储器。

基本的半导体设计 双极晶体管

如场效应晶体管，双极晶体管包含p和n型材料配置输入，中间和输出地区。然而，在双极晶体管，这些地区被称为发射基地，和集电极。双极晶体管，而不是依靠一个辅助电压源，改变门下方的极性（场效应），场效应管做，使用辅助电压源提供足够的能量，为电子打穿了反向偏置的基极 - 集电极结（见附图）。电子带电所以请注意，即使使用高能量的电子，p型材料的中间部分必须是非常薄的电子通过两个路口。

所有的集成电路都使用相同的电压基本原则（V）电流（I），电阻（R）。特别是，根据欧姆定律：V = IR方程，确定许多电路设计选择。设计工程师还必须熟悉不同的应用程序所需的各种电子元件的性能。

设计集成电路

模拟设计

如前所述，模拟电路需要无级变速的现实世界中的电压或电流，并修改了一些有用的方式。相比，与另一个信号，与其他信号从其他信号

分离，研究价值，或以其他方式操纵混合信号可能被放大。对于这种类型的电路设计，每一个单独的组件，尺寸，位置，和连接的选择是至关重要的。独特的决策比比皆是，例如，一个连接是否应该略宽比另一个方面，一个电阻是否应该到另一个方向平行或垂直，或是否在另一个上面可以躺在一条线。每个小细节影响最终产品的最终性能。当集成电路要简单得多，元件值，可通过手工计算。例如放大器（增益），特异性扩增值通常可以从两个特定的电阻率计算。然后可以决定在电路中的电流，使用放大器的增益和使用的电源电压所需的电阻值。随着设计变得更加复杂，实验室测量结果被用来描述设备。工程师提请跨越几个变量的器件特性的图形，然后提到这些图，因为他们需要为他们的计算信息。作为科学家提高他们对每个设备的复杂物理特性，他们开发了复杂的方程，考虑到了微妙的影响，和没有仔细得在实验室测量。例如，晶体管的工作在不同的频率，大小，方向和投放位置都不一样。科学家们发现，对于设备的构建方式所固有的寄生元件有影响（不必要的影响，通常是电阻和电容）。

设计集成电路 数字化设计

由于数字电路模拟电路涉及的组件有数百万个，大部分的设计工作是完成复制和重复使用相同的电路功能，尤其是通过使用数字化设计软件，包含的prestructured电路元件库。在这样一个高度精细的元器件库，使他们结合在一起。无论电脑配置如何布局，SPICE是完全足够以分析与方程描述各个组件的模拟电路。因此，数字化分析软件将忽略整个预先设定的电路块（或逻辑功能）数学模型的各个组件。此取决于是否使用模拟或数字电路的电路功能。时间，创新和经验，使得模拟电路的设计和布局将会变得更加困难，特别是对于频率较高的电路，虽然一个很大的好处是监督一个自动化的过程，以及熟练的数字设计和布局控制。

数字化设计，结果是模拟设计不同的功能。