E i e v e c e i b e f when the materials are brought into contact with one another, they are not in equilibrium e fs. September 24, 2011 national semiconductor becomes part of texas instruments. Semiconductor materials presents physicochemical, electronic, electrical, elastic, mechanical, magnetic, optical, and other properties of a vast group of elemental, binary, and ternary inorganic semiconductors and their solid solutions. An ohmic contact is a nonrectifying electrical junction. Metal semiconductor contact rectifying schottky junction nonrectifying ohmic contacts slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Gilbert ece 340 lecture 35 111611 ideal metalsemiconductor contacts we talk a lot about semiconductors, but how do we contact them. In this study, we have chosen the most commonly used contact test structures to measure contact resistance rc and extract. Metal semiconductor contacts are an obvious component of any semiconductor device. Chapter 4 metalsemiconductor contacts and semiconductorsemiconductor heterojunctions 4.
For a sufficiently large schottky barrier height, where. Pdf metalsemiconductor contact in organic thin film. It is well known that the quality of metalsemiconductor contacts plays an important role in the performance of various semiconductor devices and integrated circuits. The metal semiconductor ms contact is an important component in the performance of most semiconductor devices in the solid state. Shorted metal and semiconductor, with surface states, in physical contact when the density of surface states is high, as it typically is, the potential barrier that develops is dominated by the location of the surface states in the semiconductor band. Rhoderick, 1988, clarendon press, oxford university press edition, in english 2nd ed. Dieter schroder from arizona state university for his generous contributions and freely given resources. Metalsemiconductor contacts schottky contacts metal on lightly doped silicon rectifying ohmic contacts metal on heavily doped silicon low resistance 2 november.
Recent citations accurate evaluation of specific contact resistivity between inasni inas alloy using a multisidewall transmission line method kei sumita et al. Metal semiconductor junction metallization semiconductor. The effect of electric field on the semiconductor surface before proceeding with detailed consideration of the sisio 2 interface, capacitancevoltage analysis, device structures, etc. Metalsemiconductor contacts monographs in electrical and electronic engineering rhoderick, e. The threedimensional contact system has no restriction in the topology. In this chapter, we are concerned with the basic physical principles, electrical properties, and applications of the metalsemiconductor contacts and devices.
This type of contact is also described as metallization, and is used to supply electric current into semiconductor devices. Just enter the term that you would like to have explained and start the search. The intrinsic semiconductor material is converted to extrinsic one by adding on impurities of pentavalent or trivalent atoms in semiconductor. Metalsemiconductors contacts engineering libretexts. Whether a given metalsemiconductor junction is an ohmic contact or a schottky barrier depends on the schottky barrier height. This test pattern will be inserted in a test vehicle dedicated to monitor this process. Metalsemiconductor contacts are an obvious component of any semiconductor device. The dashed line at the top represents the zero of energy at infinity. Here we will discuss the rectifying contact, sometimes called the schottky barrier contact. Schottky barrier models 1 the schottkymott model according to schottky and mott 1938 the height of the barrier between a metal and an ntype semiconductor is given by q. To investigate the ni contact further, r c was measured at low temperature via tlm, as shown in figure 4, for a 6nm. This type of contact yields a linear relationship between the voltage applied and the current that flows across the junction. New technical approaches and higher materials and algan gan heterointerface quality are required in order to eliminate the above problems.
Metalsemiconductor contact in organic thin film transistors article pdf available in journal of materials chemistry 1845. Alan doolittle school of electrical and computer engineering. Structurerelated interface dipoles the barrier heights of typeb and typea nisisklll contacts measure 0. The semiconductor material in pure form is known as intrinsic semiconductor and in impure form it is called extrinsic semiconductor material. Metalsemiconductor contacts 1988 edition open library. Work purpose the determination of the potential difference that appears at the contact surface between a metal and a semiconductor, potential difference that is known under the name of contact, or diffusion, bias. Erbium silicided schottky sourcedrain silicon nanowire n. This book deals with the basic science of such contacts, and discusses the electrical properties that are relevant to semiconductor technology. Save as pdf metaloxidesemiconductorfieldeffecttransistor nonideal pn junction diodes. Low resistance ohmic contacts are used to allow charge to flow easily in both directions between the two conductors, without blocking due to rectification or excess power dissipation due to voltage thresholds. Metalsemiconductor ohmic contacts stanford university. Nov 02, 2015 metalsemiconductor contacts kasif nabi imi2015007 department of microelectronics indian institute of information technology allahabad 2nd november 2 november 2015 1 2. Materials science in semiconductor processing provides a unique forum for the discussion of novel processing, applications and theoretical studies of functional materials and devices for optoelectronics, sensors, detectors, biotechnology and green energy. As with all of these lecture slides, i am indebted to dr.
Ideal mos structure at zero bias reading assignment. May 5, 1999 national semiconductor exits the pc processor business to sharpen the companys focus on the emerging information appliance market and on its traditional analog business. The work functions of the metal and semiconductor have been labelled. In this chapter, we are concerned with the basic physical principles, electrical properties, and applications of the metal semiconductor contacts and devices.
Metalsemiconductor contacts 1988 edition open library donate. Semiconductor device and material characterization dr. Metal semiconductor junction and band model of pn junctions. The term metal silicon contact includes silicidesi contacts.
The metal work function is greater than the n type semiconductor work function the metal work function is lower than ptype semiconductor work function very high density of surface states pinning the fermi level at the surface w. At the same time, such contacts cannot be assumed to have a resistance as low as that of two connected metals. Contact resistance to a thin semiconductor layer print file in pdf format. Topics covered include the currentvoltage relationship, the capacitance of rectifying contacts, and practical methods of fabricating contacts. Metalsemiconductor contacts monographs in electrical and.
Doitpoms tlp library introduction to semiconductors metal. The schematic below shows a metal and an ntype semiconductor. Contact resistance to a thin semiconductor layer the contact between a metal contact and a thin conducting layer of semiconductor can be described with the resistive network shown infigure 3. Written for semiconductor technologists and physicists engaged in research on semiconductor interfaces, this text emphasizes practical implications wherever they are relevant to device technology. Tunneling ohmic contacts an ohmic contact is defined as one in which there is an unimpeded transfer of majority carriers from one material to another, i. Gaas schottky contact n doped electrons from conduction band or in the metal. It is well known that the quality of metal semiconductor contacts plays an important role in the performance of various semiconductor devices and integrated circuits. The way to achieve such a contact is by doping the semiconductor heavily enough that tunneling is possible. National semiconductor advanced peripherals data communications local area networks uar ts handbook ocr. National semiconductor company and contact information.
Theory when two substances are in contact, between them there is a charge. Current transport as a function of schottky barrier height. Metal semiconductor metal photodetectors based on grapheneptype silicon schottky junctions yanbin an,1,a ashkan behnam,2,a eric pop,2,3 and ant ural1,b 1department of electrical and computer engineering, university of florida, gainesville, florida 32611, usa. This filled band, however, overlaps with the next higher band, therefore they are conductive but with slightly higher resistivity than normal metals b. The effect of physical characteristics such as metalsilicided junction depth, number of sinw channels, and metalsemiconductor junction size were investigated and found to have a direct effect on the electrical performance of the devices. Analytical model of the metalsemiconductor contact for.
In this chapter, the basic device physics, the electrical and transport properties, and the formation and characterization of various metalsemiconductor contacts are presented. In particular, a large mismatch between the fermi energy of the metal and semiconductor can result is a highresistance rectifying contact. Metalsemiconductor contacts energy band alignment fermilevel pinning current transport and barrier height extraction measurement of r c and. Each issue will aim to provide a snapshot of current insights, new achievements. Products include power and signal management, logic, discrete, and custom devices for automotive, communications, computing, consumer, industrial, led lighting, medical, militaryaerospace and power applications.
The process of introduction of impurities in semiconductors in a. On semiconductor is a fortune 500 semiconductors supplier company. It also discusses the properties of organic semiconductors. As the name implies, the ms junction is that a metal and a semiconductor material are contacted closely. Metals, semiconductors, and insulators metals have free electrons and partially filled valence bands, therefore they are highly conductive a.
Metalsemiconductormetal photodetectors based on grapheneptype silicon schottky junctions yanbin an,1,a ashkan behnam,2,a eric pop,2,3 and ant ural1,b 1department of electrical and computer engineering, university of florida, gainesville, florida 32611, usa. Unlimited viewing of the articlechapter pdf and any associated supplements and figures. Achieving low contact resistivity at the source and drain regions are among the key challenges in which it is highly dependent on the metalsemiconductor contact interface and is a topic of keen. It is therefore called an ohmic contact, because it obeys ohms law. Basically, there are two types of ms contacts that are widely used in semiconductor devices. Shorted metal and semiconductor, with surface states, in physical contact when the density of surface states is high, as it typically is, the potential barrier that develops is dominated by the location of the surface states in. Gilbert ece 340 lecture 35 111611 ideal metal semiconductor contacts now lets bring the metal and semiconductor together e 0 m s metal semiconductor ntype s e c e fs e v e fm m. B is significantly higher than the thermal energy kt, the semiconductor is depleted near the metal and behaves as a schottky barrier. Because the conduction band in the semiconductor is energetic higher than the fermi level, electrons flow into the metal since they always want to achieve the lowest energy state. Metal semiconductor contacts and devices issn kindle edition by cohen, simon s. Semiconductor potential poisson and carrier continuity eqns effect of minority carriers is neglected neglecting the semiconductor depletion width only need to solve the majority carrier continuity eqn in the semiconductor region under the contact. What does one have to do for a metal semiconductor junction to. Apr 10, 2015 metal semiconductor contact rectifying schottky junction nonrectifying ohmic contacts slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Chapter 4 metalsemiconductor contacts and semiconductor.
Schenk et al analytical model of the metalsemiconductor contact for device simulation the wkb approximation is bypassed by interpolating analytically between the asymptotic forms of the eigenfunctions parabolic cylinder functions by means of airy functions. Metal semiconductor contacts and devices issn, cohen. Contact resistance in emerging materials germanium mos 2 25022016 2. The rectifying properties of a metalsemiconductor contact arise from the presence of an electrostatic barrier between the metal and the. Achieving low contact resistivity at the source and drain regions are among the key challenges in which it is highly dependent on the metal semiconductor contact interface and is a topic of keen. The effect of electric field on the semiconductor surface. Conduction mechanisms for metalnsemiconductor contacts as a function of the barrier height and width. Metalsemiconductor contacts kasif nabi imi2015007 department of microelectronics indian institute of information technology allahabad 2nd november 2 november 2015 1 2. In this letter, we report on the performance of ganbased thin channel highly doped metal semiconductor. Suppose we have a ptype material and metal contacts deposited taking the work function of a metal and.