Schottky diodes junction barrier

In the following analysis, both p-z-n and junction barrier Schottky diodes will be evaluated for use in a 3-kV, 30A SiC bridge rectifier module. Four of these modules will replace the 10 Si diode bridge rectifiers and will reduce system volume and increase efficiency. To optimize the design of the module, we will evaluate the power density at the die level as a function of the number of paralleled diodes in each rectifier leg. A typical value of the heat-transfer coefficient of conventional, power components is 100 W/cm In the present analysis, we have a design limit of 200 W/cm and will determine the number of JBS and p-z -n diode needed to meet this goal. 

SiC p-n junction and Schottky barrier diodes C SCHOTTKY BARRIER DIODES... 

LEDs are made from boron-doped 4H-SiC. Three colour displays have been demonstrated. SiC ultraviolet photodetectors made from p-n junction and Schottky barrier diodes can be used up to temperatures of 700 K and are expected to be radiation tolerant. These photodiodes are more sensitive than their silicon counterparts. 

Cryogenically cooled detectors employ the low-noise GaAs Schottky barrier Mott diodes. Between 140 and 220 GHz they exhibit 400 K noise equivalent temperature at a lower limit junction temperature of 20 K, below which the performance degrades. The noise temperature is around 1000 K at 300 K junction temperature. Sensitivity of a Schottky barrier mixer diode ranges from about 2.75 VmW" to 1 VmW over the range 90-325 GHz.In comparison the helium-cooled InSb bolometer used by the present authors (Section 3.4.1) can provide double sideband noise temperatures of 200-300 K in the region 100-300 GHz and sensitivity of 5-6 VmW . ... 

Any other form of internally generated noise must depend upon bias. Since they add (quadratically) to Johnson noise, all other types of noise are referred to as excess noise. Three principal forms of excess noise exist. One amenable to analysis which is found in photoconductors is generation-recombination or g — r noise. A second, also amenable to analysis, which is found in photodiodes, i.e., p - n junctions and Schottky barrier diodes, is referred to as shot noise of diffusing carriers, or simply as shot noise. The third form of excess noise, not amenable to exact analysis, is called l//(one over/) noise because it exhibits a 1// power law spectrum to a close approximation. It has also been called flicker noise, a term carried over from a similar power law form of noise in vacuum tubes. 

The terms anti-barrier and non-directing junction are used in the further text both for isotype semiconductor homo- or heterojunctions and for the corresponding Schottky junctions, while the terms barrier and directing junction are used to denote p-n junctions (both homo- and heterojunctions) and Schottky diode junctions. 

The forward and reverse characteristics for a Schottky diode formed with an aluminium/polyacetylene Schottky junction and a gold ohntic contact (polyacetylene thickness 500 nm) is shown in figure 13. This device shows a particularly good characteristic with a high forward te reverse ratio which reaches a maximum of S x 1(P at a bias of 1.5 V, and is lintited at this value by the high bulk resistance of the undepleted polyacetylene layer. We note that this value is very much higher than values found previously for Schottky barriers formed with Shirakawa polyacetylene and other conjugated polymers [57-62,64]. 

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