Us6437399b1 semiconductor structures with trench contacts. Metalsemiconductor contacts fermi level pinning is the lack of barrier height modulation with metal work function due to either large density of intrinsic states. High speed devices and circuits lecture metal semiconductor contacts for mesfet contd. It is thus a kind of schottky barrier detector, but with two schottky junctions. Pdf the study of ohmic contacts to wide bandgap semiconductors proves. The effect of interface states on the barrier heights of metal semiconductor contacts was first analyzed by cowley and sze 33. An ohmic contact is a nonrectifying electrical junction. Contact resistance to a thin semiconductor layer print file in pdf format. The physics of carrier transport across the metalsemiconductor junction renders metal contacts either rectifying a. It is well known that the quality of metalsemiconductor contacts plays an important role in the performance of various semiconductor devices and integrated circuits.
This course presents indepth discussion and analysis of pn junction and metalsemiconductor contacts including equilibrium behavior, current and capacitance responses under bias, breakdown, nonrectifying behavior, and surface effect. This report describes the research accomplished during the last twelve months of a 20month program of research on metal contacts to the semiconductor indium phosphide inp. A metal semiconductor junction results in an ohmic contact i. I want to fabricate a pn junction device consisting of a ptype material on ntype silicon.
Metal semiconductor interfaces rectifying schottky junction nonrectifying ohmic contacts 4. Twodimensional transition metal dichalcogenides are promising candidates for ultrathin optoelectronic devices due to their high absorption coefficients and intrinsically passivated surfaces. Metalsemiconductor contacts monographs in electrical and electronic engineering. Rhoderick, 9780198593362, available at book depository with free delivery worldwide. Basically, there are two types of ms contacts that are widely used in semiconductor devices. Niauge for ntype gaas are the most commonly used contacts for gaas and inp materials for both n and ptype contacts due to the excellent contact resistivity, reliability, and usefulness over a wide range of doping levels. Metalsemiconductormetal photodetectors rp photonics. Hot electrondriven electrocatalytic hydrogen evolution. At the same time, it is known that lapped silicon surface has a. A metalsemiconductormetal photodetector msm detector is a photodetector device containing two schottky contacts, i.
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. The metal semiconductor ms contact is an important component in the performance of most semiconductor devices in the solid state. Metal semiconductor contacts and devices, volume 1st. Metalsemiconductor contacts kasif nabi imi2015007 department of microelectronics indian institute of information technology allahabad 2nd november 2 november 2015 1 2.
The schottky barrier energy phi sub b and the contact resistance rc were measured for several metalinp structures and the electrical properties were correlated to the. Process engineers, device physicists, circuit designers, and students of this discipline will find the book very useful. Challenge of applying ohmic contacts to gallium arsenide. Metalsemiconductor ohmic contacts rcsd r dp rext rov x y 0 sidewall gate silicide nextx novy year 1997 1999 2003 2006 2009 2012 min feature size 0. The metal oxide semiconductor field effect transistor mosfet is one of the cornerstones of modern semiconductor technology. Metal semiconductor ohmic contacts rcsd r dp rext rov x y 0 sidewall gate silicide nextx novy year 1997 1999 2003 2006 2009 2012 min feature size 0. In this chapter, we are concerned with the basic physical principles, electrical properties, and applications of the metalsemiconductor contacts and devices. Doitpoms tlp library introduction to semiconductors. Lecture 17 metalsemiconductor junction march 14, 2007 contents. It is the minimum energy required to free up electrons from metal. The drift velocity attained by the carriers in the presence of an external field is determined by the free time available to the. A short discussion is also given of practical contacts and their application in semiconductor technology, and a comparison is made with pn junctions. Moreover, metalsilicon contacts in dislocation free silicon are rectifying 19. Metal semiconductor interfaces rectifying schottky junction nonrectifying ohmic contacts 3.
Metalsemiconductor ohmic contacts stanford university. Poissons equation, work function, ms energy band diagrams lecture 9. In such case, the carriers are free to flow in or out of the semiconductor so that there is a minimal resistance across the contact. In such case, the carriers are free to flow in or out of the semiconductor so that. Metal semiconductor contacts and devices issn kindle edition by cohen, simon s. Importance of metalsemiconductor contacts is due to l ohmic metalsemiconductor junctions e.
Ideal metalsemiconductor junction outside equilib rium reading assignment. Barrier height studies on metalsemiconductor systems core. 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. Barrier height ohmic contact schottky barrier schottky diode schottky barrier height. Metal semiconductor contacts and devices by simon s. Download citation metalsemiconductor contacts in this chapter, the basic device. Metal semiconductor contact anchit biswas techno india,saltlake 2. Ee lecture notes university of california, berkeley. Metalsemiconductor contacts 1988 edition open library. As the name implies, the ms junction is that a metal and a semiconductor material are contacted closely. To achieve ohmic contact on ntype silicon, which metals would be good. Us09498,476 19970630 20000204 semiconductor structures with trench contacts expired lifetime us6437399b1 en. Written for semiconductor technologists and physicists engaged this second edition brings a greatly expanded treatment of the physics of schottkybarrier formation to its comprehensive discussion of.
Metalsemiconductor contacts are an obvious component of any semiconductor device. The small barrier that exists for electron flow from metal to the semiconductor, but vanishes when. The term metal silicon contact includes silicidesi contacts. For a sufficiently large schottky barrier height, where. Ohmic contacts common techniques to make ohmic contacts choose metal so that its work function fmetal is close to that of semiconductors fsemi thermal ionic insert thin layer of narrow bandgap material between metal and semiconductor increase the doping level near the semiconductor surface as high as possible tunneling assisted. Ideal metalsemiconductor contacts assumptions ideal ms contacts metal m and semiconductor s are in intimate contact, on atomic scale no oxides or charges at the interface very bad assumption in some cases some interfaces are dominated by inte rfacial oxides or interface charge. Herein, we demonstrated the conversion of the schottky nature of the nisi junction, one of the most commonly used metalsemiconductor junctions, into an ohmic contact with low contact resistance by inserting a single layer of. Metalsemiconductor contacts schottky contacts metal on lightly doped silicon rectifying ohmic contacts metal on heavily doped silicon low resistance 2 november. A fundamental study of advanced metalsemiconductor contacts. Use features like bookmarks, note taking and highlighting while reading metal semiconductor contacts and devices issn. For the love of physics walter lewin may 16, 2011 duration. Semiconductor physics, quantum electronics and optoelectronics.
Metal semiconductor contacts are an obvious component of any semiconductor device. A metal semiconductor contacts without interface states. To achieve ohmic contact on ntype silicon, which metals. Metalsemiconductor barrier height measurement by the differential capacitance methodone.
Topics covered include the currentvoltage relationship, the capacitance of rectifying contacts, and practical methods of fabricating contacts. 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 general structure is a lightly doped ptype substrate, into which two regions, the source and the drain, both of heavily doped ntype semiconductor have been embedded. The schottky barrier energy phi sub b and the contact resistance rc were measured for several metal inp structures and the electrical properties were correlated to the. Written for semiconductor technologists and physicists engaged in research on semiconductor interfaces, this text emphasizes practical implications wherever they are relevant to device technology. Purchase metal semiconductor contacts and devices, volume 1st edition. Department of electronics engineering, national chiao tung university, hsinchu, taiwan. Theory when two substances are in contact, between them there is a charge. For example, good ohmic contacts are essential for achieving excellent performance of a semiconductor device, while schottky i. A nonrectifying contact whose relationship between current and voltage has a low interfacial contact resistance r c, and is preferably linear, is referred to as an ohmic contact. Metalsemiconductor interfaces rectifying schottky junction nonrectifying ohmic contacts 3. Metalsemiconductor contacts monographs in electrical and.
It is well known that the quality of metalsemiconductor contacts plays an. Topics covered include the factors that determine the height of the schottky barrier, its currentvoltage characteristics, and its capacitance. B is significantly higher than the thermal energy kt, the semiconductor is depleted near the metal and behaves as a schottky barrier. Metalsemiconductor interfaces rectifying schottky junction nonrectifying ohmic contacts 4. In addition to different device and circuit applications, schottky contacts can also. This course can also be taken for academic credit as ecea 5631, part of cu boulders master of science in electrical engineering degree.
Lecture 12 metal semiconductor contacts for mesfet. In this chapter, we are concerned with the basic physical principles, electrical properties, and applications of the metal semiconductor contacts and devices. The schematic energy band diagram under equilibrium conditions for a metal in free space is shown in figure 10. The physics of carrier transport across the metal semiconductor junction renders metal contacts either rectifying a. Pdf ohmic contacts for high power and high temperature. Degenerate semiconductor materials tend to act more like a metal than as a semiconductor due to high doping. May 18, 2020 the metalsemiconductor ms contact is an important component in the performance of most semiconductor devices in the solid state. Graphene for true ohmic contact at metalsemiconductor. Nov 02, 2015 metalsemiconductor contacts kasif nabi imi2015007 department of microelectronics indian institute of information technology allahabad 2nd november 2 november 2015 1 2. A nonrectifying contact whose relationship between current and voltage has a low interfacial contact resistance r c.
Introduction metal semiconductor junctions a wide range of metals, such as silver ag, gold au, copper cu, aluminum al and alloys are used to make electrical contacts to semiconductors. To maintain these nearperfect surfaces, recent research has focused on fabricating contacts that limit fermilevel pinning at the metalsemiconductor interface. Usually, for alfree contacts refractory metals having a high work function andor. Topics covered include the factors that determine the height of the schottky barrier. Metalsemiconductor junction an overview sciencedirect topics. The semiconductor structure of claim 11 wherein said metal comprises a vertical metal filled trench disposed substantially above said region of high impurity concentration.
Dec 07, 2007 for the love of physics walter lewin may 16, 2011 duration. As the name implies, the ms junction is that a metal and a metalsemiconductors contacts engineering libretexts. The junctions formed at the contact between metallic electrodes and semiconductor materials are crucial components of electronic and optoelectronic devices. Whether a given metalsemiconductor junction is an ohmic contact or a schottky barrier depends on the schottky barrier height. Metal semiconductor contacts and devices, volume 1st edition. Surface states and fermi level pinning metalsemiconductor. Lecture metal semiconductor contacts for mesfet contd. The rectifying schottky characteristics of the metalsemiconductor junction with high contact resistance have been a serious issue in modern electronic devices. Apr 20, 1978 topics covered include the currentvoltage relationship, the capacitance of rectifying contacts, and practical methods of fabricating contacts. Metalsemiconductors contacts engineering libretexts. Prior to cleaving, ohmic contacts were made to the ends of the bars. Conduction mechanisms for metalnsemiconductor contacts as a function of the barrier height and width. Iv characteristics few minority carriers anywhere majority carrier device bottleneck. Metal semiconductor contacts and devices issn, cohen.
A metalsemiconductor junction results in an ohmic contact i. Metalsemiconductor contacts monographs in electrical and electronic engineering rhoderick, e. The metalsemiconductor ms contact is an important component in the performance of most semiconductor devices in the solid state. Iv characteristics, practical ohmic contacts, smallsignal capacitance pn junction diodes lecture 10. Importance of metal semiconductor contacts is due to l ohmic metal semiconductor junctions e. Dec 08, 2007 high speed devices and circuits lecture metal semiconductor contacts for mesfet contd.
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