Abstract
The effects of selective reactive ion etching (SRIE) using SiCl4/SiF4 plasma on delta-doped GaAs/Al0.3Ga0.7As modulation-doped field-effect transistor (MODFET) structures and devices have been investigated. The results are compared with those of corresponding conventionally doped MODFETs. Hall measurements were conducted at 300 and 77 K to characterize the change in the transport properties of the two-dimensional electron gas due to low energy ion bombardment during the SRIE process. Delta-doped structures showed a smaller change in sheet carrier density and mobility compared to conventionally doped structures. Direct current and high frequency measurements were performed on the SRIE gate-recessed MODFETs. No significant change in threshold voltage was observed for the delta-doped MODFETs in contrast to an increase of about 300 mV for the conventionally doped MODFETs processed at a plasma self-bias voltage of −90 V and a 1200% overetch time. Maximum dc extrinsic transconductance and unity current gain cutoff frequency did not change with SRIE processing for either of the structures.
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Agarwala, S., Tong, M., Ballegeer, D.G. et al. Characterization of selective reactive ion etching effects on delta-doped GaAs/AlGaAs MODFET layers. J. Electron. Mater. 22, 375–381 (1993). https://doi.org/10.1007/BF02661665
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DOI: https://doi.org/10.1007/BF02661665