|Title:||Post-growth modulation doping by ion implantation||Authors:||Chiu P.-Y
|Keywords:||Hall mobility; Heterojunctions; Hole mobility; Ion implantation; Ions; Modulation; Semiconducting germanium; Semiconductor doping; Dopant activation; Empirical calibration; Germanium quantum wells; Growth modulation; Heterostructure field effect transistors; Model material systems; Semiconductor heterostructures; Two Dimensional (2 D); Field effect transistors||Issue Date:||2020||Journal Volume:||117||Journal Issue:||26||Source:||Applied Physics Letters||Abstract:||
Modulation doping is a commonly adopted technique to create two-dimensional (2D) electrons or holes in semiconductor heterostructures. One constraint, however, is that the intentional dopants required for modulation doping are controlled and incorporated during the growth of heterostructures. Using undoped strained germanium quantum wells as the model material system, we show, in this work, that modulation doping can be achieved post-growth of heterostructures by ion implantation and dopant-activation anneals. The carrier density is controlled ex situ by varying the ion fluence and implant energy, and an empirical calibration curve is obtained. While the mobility of the resulting 2D holes is lower than that in undoped heterostructure field-effect transistors built using the same material, the achievable carrier density is significantly higher. Potential applications of this modulation-doping technique are discussed. ? 2020 Author(s).
|Appears in Collections:||電機工程學系|
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