Doping semi-insulating material

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 ... 

Because of the low surface recombination velocity of InP-related materials, planar photoconductive devices on iron-doped semi-insulating InP have been extensively studied. This material has a room temperature resistivity of 10 -10 f2-cm and an electron mobility of 1500-4500 cm /V-s depending on the crystal quality and iron concentration. The carrier Hfetime ranges from less than 1 ps to 3 ns. 

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]. 

Oxides are often chosen as insulation materials, for example as sheaths for resistive heaters, due to their low electrical and thermal conductivity. In MOS transitors (MOS = Metal-Oxide-Semi-conductor), a thin Si02 layer is deposited between a doped silicon substrate and the metallic gate to control the channel conductivity. In more complicated electronic devices, with several integration levels, Si02 is also used to make insulating dielectric layers. 

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