Defective states in semi-insulating gallium arsenide substrates

摘要

Semi-insulating gallium arsenide substrates are widely used for microwave discrete devices and integrated circuits. However, the performance of the above devices may be significantly affected by the substrate quality, i.e. crystal defects and related deep levels. Consequently, a careful characterization of substrates is mandatory to improve both device performance and production yields. In this work we have investigated gallium arsenide substrates from different suppliers and/or differently processed. To these substrates we have applied, discussed and compared different methodologies (current-voltage and capacitance-voltage characteristics as well as spectroscopic methods) to characterize the many deep levels which are either present in as-received semi-insulating substrates or induced by device processing such as ion implantation and the subsequent thermal annealing.