专业英语2-第3讲-Chapter 3.4

Chapter 3 Processing Technology3.1 Crystal growth and epitaxy晶体生长和外延As discussed previously in Chapter 1, the two most important semiconductors for discrete分离的devices and integrated circuits are silicon and gallium镓arsenate砷酸盐.正如之前在第一章所讨论的，对于分立器件和集成电路而言, 两种最重要的半导体是硅和砷化镓。

In this chapter we describe the common techniques for growing single crystals of these two semiconductors.在本章, 我们描述生长这两种半导体单晶的常用技术。

The basic process flow is from starting materials to polished抛光wafer s.基本流程是从原料到抛光片。

The starting materials (e.g., silicon dioxide for a silicon wafer) are chemically processed to form a high-purity polycrystalline多晶semiconductor from which single crystals are grown.原材料(即，用于生长硅片的二氧化硅) 通过化学处理形成高纯度的多晶半导体以生长单晶。

di-ox-ide二-氧-化物di-chlor-ide二-氯-化物di-sulf-ide 二-硫-化物poly crystal line 多晶前缀poly-聚合、多, mulit-多single- 单The single-crystal ingot s锭are shaped to define the diameter of material and saw ed into wafers.定形后的单晶锭决定了材料的直径，并且被切成晶元。

These wafers are etch ed蚀刻and polished to provide smooth, specular surfaces on which devices will be made.这些晶圆被蚀刻和抛光以得到光滑的镜面表面，器件将制造在其表面上。

A technology closely related to crystal growth involves the growth of single-crystalsemiconductor layers upon a single-crystal semiconductor substrate基片，衬底.晶体生长密切相关的一个技术包括在单晶半导体基板上生长单晶半导体层(的技术)。

This is called epitaxy, from the Greek words epi (meaning “on”) and taxis (meaning “arrangement”).这被称为外延，来源于希腊文字中的epi（意为“on”）及taxis（意为“安排”）。

The epitaxial process offers an important means of controlling the doping profiles剖面，详细资料so that device and circuit performances can be optimized优化.外延工艺提供了控制掺杂分布，使设备和电路性能可以得到优化的重要手段。

For example, a semiconductor layer with a relatively low doping concentration浓度can be grown epitaxially upon a substrate which contains the same type of dopant掺杂剂in a much higher concentration(e.g.,n-type silicon on an n+ -silicon substrate). 例如，一个相对较低的掺杂浓度的半导体外延层可以外延生长在一个掺杂类型相同但浓度更高的的基片上（例如，n型硅生长在n+ - Si衬底硅）。

In this way the series resistance 串联电阻associated with the substrate can be substantially reduced.通过这种方式，与基板相关的串联电阻可以大幅地减少Many novel device structures, especially for microwave and photonic devices, can be made by epitaxial processes.许多新的元件结构，特别是微波和光子器件，可以通过外延法加工。

novel新颖的n. 小说Later in this chapter we consider some important epitaxial growth techniques.在本章后面，我们会介绍一些重要的外延生长技术。

3.2 Crystal Growth from the Melt从熔体生长晶体There are basically two techniques for crystal growth from the melt (i.e., material in liquid form): the Czochralski techniques and the Bridgman technique.有两种基本技术可以从熔体（即液态的材料）生长晶体：乔赫拉尔斯基法（也称为直拉法）和布里奇曼法(双温区生长法)。

A substantial percentage (-90%) of the silicon crystals for the semiconductor industryare prepared by the Csochralski technique; virtually all the silicon used for fabrication integrated circuits is prepared by this technique.一个相当大的比例（约90％）的半导体工业用的硅晶体由CZ法制备，几乎所有用于制造集成电路的硅都采用这种技术制备。

Most gallium arsenide, on the other hand, is grown by the Bridgman technique. However, the Czochralski technique is becoming more popular for the growth of large-diameter gallium arsenide.大多数砷化镓，反过来，是布里奇曼技术生长。

然而，使用Czochralski技术来生长大直径的砷化镓也越来越多（流行）。

gallium arsenide 砷化镓arsen-ide 砷化物arsenic 砷arsenate砷酸3.2.1 Starting materials 原料The starting materials for silicon is a relatively pure form of sand (SiO2) called quartzite石英岩.硅的原料是相对纯净的砂子（SiO2），称为石英岩（或硅石）。

This is placed in a furnace with various forms of carbon (coal, coke, and wood chips). While a number of reactions take place in the furnace, the overall reaction is SiC (solid) +SiO2(s) – Si(s) + SiC(g) +CO(g)石英岩与各种形式的碳（煤，焦炭和木屑）一起放置在反应炉中。

尽管反应炉中发生了很多反应，总反应是SiC Silicon carbide 碳化硅CO Carbon mono-x-ide 一氧化碳This process produces metallurgical冶金–grade silicon with a purity of about 98%. Next, the silicon is pulverized粉碎and treated with hydrogen chloride (HCL) to form trichlorosilane (SiHCl3):Si(solid) + 2HCL(gas) – SiHCl3(gas) +H2(gas)这一过程产生冶金级，纯度约98％的硅。

其次，硅被粉碎并和氯化氢（HCL）反应以形成三氯氢硅：Tri-chloro-silane 三-氯-硅烷HCL Hydrogen chlor-ide氯化氢The trichlorosilane is a liquid at room temperature (boiling point 32℃).三氯氢硅在室温时是的液体（沸点为32℃）。

boiling point 沸点melting point 熔点Fractional部分的distillation蒸馏of the liquid removes the unwanted impurities.通过精馏液体除去不需要的杂质。

distill v.蒸馏distil lation n. 蒸馏The purified SiHCl3is then used in hydrogen reduction reaction to prepare the electronic-grade silicon (EGS)：SiHCl3+ H2– Si + 3HCl纯化后的SiHCl3通过氢还原反应可以制备电子级硅（EGS）：This reaction takes place in a reactor containing a resistance-heated silicon rod, which serves as the nucleation核point for deposition of silicon.这种反应发生在一个含有电阻加热的硅棒的反应炉中，硅棒可作为硅沉积的成核点。