Nov 27, 2018

Behavior of Cu and Zn Impurities on GaAs Wafer Surfaces


Surface Cu and Zn contamination levels of intentionally contaminated GaAs wafers were measured by total reflection X-ray fluorescence (TXRF). Cu and Zn are both major metallic impurities on GaAs wafer surfaces, but their adsorption behaviors in an organic base solution were quite different. Surface concentration of Cu was much higher than that of Zn when concentrations of Cu and Zn in the organic base solution were the same. Cleaning effects of running deionized water rinse in an ultrasonic bath (U-RDIW) were also studied. Surface concentrations of Cu and Zn were drastically reduced by U-RDIW rinse.




Source:IOPscience

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Nov 12, 2018

Room-temperature GaAs/InP wafer bonding with extremely low resistance



Low-temperature direct wafer bonding is a promising technique for fabricating multijunction solar cells with more than four junctions in order to obtain high conversion efficiencies. However, it has been difficult to reduce the bond interface resistance between a GaAs-based subcell wafer and an InP-based subcell wafer. We found that a novel bonding structure comprising heavily Zn-doped (1 ×1019 cm−3) p+-GaAs and S-doped (3 × 1018 cm−3) n-InP had an interface resistance of 2.5 × 10−5 Ωcm2, which is the lowest value ever reported. This result suggests that the newly developed room-temperature wafer bonding technique has high potential to realize high-efficiency multijunction solar cells.



Source:IOPscience

For more information, please visit our website: www.semiconductorwafers.net,