Semi-insulating material

I.C.BASSIGNANA D.A.MACQUISTAN, 7th Int. Conf. on III-V Semi-insulating materials, Ixtapa Mexico, (1992). 

There have been a few reports on radiation damage in SiC [7]. In this area, the effects of ions and electrons have been considered. If irradiation is performed, six deep states are produced in 6H-SiC. These states have been denoted E1-E4, Z, and Z2. After thermal annealing, only the two Z states remain. It should be noted that these are the same Z states observed in as-grown bulk material. It should also be noted that the defects reported are rather shallow in energy and there are no reports of semi-insulating material produced by radiation damage. 

Fio. 2. Experimental arrangement for measuring/< in semi-insulating materials. The sample is located in a Dewar between the magnet poles. E, vibrating reed electrometer R, recorder and digital data processor F, feedback-driven shields P, potential probes M, current meter. 

The long relaxation time = e K/o in semi-insulating materials makes it possible to pull a pulse of excess charge through the material of length L and measure the drift velocity... 

A powerful method for studying the space charge regions and trap distributions at the interfaces and in the bulk of semi-insulating materials was recently developed by Simmons and Taylor (1972a, 1972b, 1973), Simmons and Nadkarni (1972), Nadkarni and Simmons (1972,1973). 

Morris, R., Dowsett, M., Chang, R. (2006) Different optical conductivity enhancement (OCE) protocols to eliminate charging during ultra low energy SIMS profiling of semiconductor and semi-insulating materials. Applied Surface Science, 252,7221-7223. 

The redistribution of Cr in doped semi-insulating material was studied by using secondary ion mass spectrometry. Marked Cr out-diffusion was observed from specimens which were annealed above 800C. The diffusion coefficient of Cr in GaAs could be described by ... 

T. Kawase, Y. Yagi, M. Tasumi, K. Fujita, R. Nakai, 1996, in 1996 IEEE Semiconducting and Semi-insulating Materials Conference, IEEE SIMC-9, Toulouse 1996 (Ed. C. Fontaine) IEEE, Piscataway, p. 275. 

K. Sumino and I. Yonenaga, 1992, "Dynamic characteristics of dislocations and mechanical behavior of 111-V-materials , 7th Corf, on Semi-insulating Materials, Ixtapa, Mexico, 29 28. 

The main advantages that compound semiconductor electronic devices hold over their siUcon counterparts He in the properties of electron transport, excellent heterojunction capabiUties, and semi-insulating substrates, which can help minimise parasitic capacitances that can negatively impact device performance. The abiUty to integrate materials with different band gaps and electronic properties by epitaxy has made it possible to develop advanced devices in compound semiconductors. The hole transport in compound semiconductors is poorer and more similar to siUcon. Eor this reason the majority of products and research has been in n-ty e or electron-based devices. 

High-purity semi-insulating (SI) SiC material has the highest reported thermal conductivity with a value of 4.9 W/(cm-K). Lower values are measured for the doped crystals but they are all above 4 W/(cm-K) at room temperature [10]. 

One of the prime advantages of the HTCVD approach is the resulting crystal properties. Due to the high purity of the gases, the material comes out intrinsically semi-insulating. Also, since the source material is produced on demand, the stoichiometry can always be kept the same, unlike the case with seeded sublimation growth. This will improve the yield of the grown material. 

A GaN substrate would be a help in this respect but it would need to be semi-insulating. In addition, GaN has a poor thermal conductivity and is not very suitable due to this negative material property. Aluminum nitride substrates may become the substrate of choice for GaN high-frequency applications. It has a reasonable thermal conductivity and is intrinsically semi-insulating but only time will tell. 

Rees, G. J., ed. (1980). Semi-Insulating III-V Materials, Nottingham, 1980. Shiva Publ, Orpington, UK. 

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