P-n diode

A small Schottky rectifier with a current rating of about 20 to 30 percent of the MOSFET current rating (/d) is placed in parallel with the MOSFET s intrinsic P-N diode. The parallel schottky diode is used to prevent the MOSFET s intrinsic P-N diode from conducting. If it were allowed to conduct, it would exhibit both a higher forward voltage drop and its reverse recovery characteristic. Both can degrade its efficiency of the supply by one to two percent. 

Schottky and P-N diodes measured at rated reverse voltage. 

Each individual p-n diode or n-p-n transistor can be made almost unbelievably minute by these techniques for example computer memory units storing over 10 bits of information on a single small chip are routinely used. Further information can be obtained from textbooks of solid-state physics or electronic engineering. 

The incorporation of phosphorus yields fourfold-coordinated P atoms, which are positively charged, as phosphorus normally is threefold coordinated. This substitutional doping mechanism was described by Street [52], thereby resolving the apparent discrepancy with the so-called S N rule, with N the number of valence electrons, as originally proposed by Mott [53]. In addition, the incorporation mechanism, because charge neutrality must be preserved, leads to the formation of deep defects (dangling bonds). This increase in defect density as a result of doping explains the fact that a-Si H photovoltaic devices are not simple p-n diodes (as with crystalline materials) an intrinsic layer, with low defect density, must be introduced between the p- and n-doped layers. 

Electroluminescent devices were made to demonstrate the possible application of these a-Si H materials. Er-doped p-n diodes in c-Si show electroluminescence, both in forward and reverse bias [670-672]. Under forward bias the electrolu-... 

Figure 11.6. Crossed nanowire p-n diode, (a) A typical SEM image of a crossed NW p-n diode, (b) Current-voltage (I-V) relation of the crossed p-n diode. Linear or nearly linear I-V behavior of the p-type and n-type NWs indicates good contact between NWs and metal electrodes. I-V curves across the junction show clear current rectification, (c) An SEM image of an NW p-n diode array, (d) I-V behavior for a 4(p) x l(n) multiple junction array. [Adapted from Ref. 57.]... 

Figure 3.10 Bidirectional switch using SiC gate turnoff thyristors and p-/-n diodes.

The first report of an all-SiC, three-phase dc-ac inverter was presented by Seshadri et al. [17] in 1999. Although Seshadri s inverter used SiG GTOs and p-/-n diodes, it was operated at ambient temperature and at voltage and current levels so low that the authors were unable to ...determine typical switching characteristics of the individual SiG components. From the standpoint of technology development, there exists a need to evaluate SiC technology under relevant circuit stresses. 

In 2001, the authors of this chapter developed a 400-W, dc-to-ac inverter using SiC GTOs and p-/-n diodes for operation at case temperatures up to 150°C for driving three-phase, inductive loads up to 5 SOW. The inverter circuit was constructed to perform the first characterization of these SiC devices under significant electrical and thermal stresses, investigate the parametric operating space of the SiC devices, and uncover circuit-related failure modes. 

Ion implantation appears as the only feasible method to accomplish selective area doping of SiC in planar device technology. As described in this chapter, substantial progress has been made during recent years but several fundamental issues and technology barriers remain before the implantation process is fully developed and can be truly implemented in SiC device processing. Eor instance, mesa-etched p n-diodes... 

The simplest electronic devices, such as diodes, light-emitting diodes, lasers, and photocells, have a single p-n junction. If we place, say, a p-type doped Si block in contact with n-typed doped Si block, electrons will normally flow from the n to the p regions but not vice versa. Thus, the p-n diode so created can be fitted with ohmic contacts to function as a rectifier of alternating current. Schottky junctions can act in this way to some degree even without deliberate creation of a p-n junction. 

Figure 7 Schematic diagrams of a trench structure carved in a p-n diode (a) side view of the trench structure that illustrates how hght is produced by tlie forward-biased diode (LED) and detected by the reverse-biased diode (photodiode) (b) top view of these LED/ photodiode pairs on a wafer. (Adapted from Ref. 14.)...

This notation, where n-type refers to an electron conductor, and retype refers to a hole (lack of electron) conductor, indicates how a semiconductor was processed. For example, a p-type semiconductor material layer grown on an n-type substrate forms a (p — n) diode, which can be used to rectify alternating current. A p — n — p device may be used as a transistor, and is useful as a signal amplifier or for other applications. 

Measured for a polycrystalline p/n diode assembly based on Fe203. Poor efficiency attributed to the non-optimal charge transfer properties of the oxide. 202... 

Since the cross section of planar surface cell LECs can be imaged by a microscope, a number of interesting experiments can be done to investigate the operation mechanisms. In a p-n diode, there is a built-in electric field at the p-n junction. This field can be measured by optical beam induced current (OBIC) microscopy, a technique in which a focused laser beam is scanned across the device while the photocurrent is monitored. When the beam excites a region that... 

VACANCY AND VACANCY-OXYGEN CLUSTERS IN EPI-Si p -n DIODES IRRADIATED WITH MeV ELECTRONS AT ELEVATED TEMPERATURES... 

Vacancy-related complexes which were generated in silicon p -n diodes by irradiation with 6 MeV electrons in the temperature range of 350-800 K have been studied by means of deep level transient spectroscopy. Such defects are of interest because of their possible application in controlling the carrier lifetime in silicon power devices. Electronic parameters of defects incorporating up to three vacancies and an oxygen atom have been detemiined. Total introduction rate of radiation-induced defects increased about twice upon raising the irradiation temperature from 350 to 675 K. 

The p -n diodes were irradiated with 6 MeV electrons using a linear accelerator. The flux of electrons was IxlO cm V and temperature of the samples during irradiation varied in the range of 300-800 K. The accumulated dose of electrons was 8xl0 cm. Thermal annealing of the irradiated structures was carried out in a furnace in nitrogen ambient. 

Fig. 1 shows DLTS graphs, which were recorded on the epi-Si p" -n diodes after irradiations with 6 MeV electrons at 350 K. 

---