M01900 - SEMI M19 - Specification for Electrical Properties of Bulk Gallium Arsenide Single Crystal Substrates

For the specification, three principal types of material were identified: semi-insulating, n-type, and p-type. This encompasses the full range of conductivity characteristics for gallium arsenide (GaAs). § 3 considers subclasses of these characteristics defining the species which may be used for producing the conductivity type. For semi-insulating material, special cases have been isolated. 　 Undoped, Grade A1 represents those materials which are of high resistivity and stable following growth, without necessitating any additional annealing or processing. The Grade A2 material, "high purity", requires additional thermal processing following growth to bring the resistivity to a level > 107 Ω-cm. At this time, most producers have indicated that the majority of the Grade A2 ingots have resistivity characteristics which rise into the acceptable range after an appropriate thermal cycle. However, this phenomenon is sensitive to the details of the time-temperature cycle, and thus, such an