Post-growth modulation doping by ion implantation

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...

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Bibliographic Details
Published in:Applied physics letters 2020-12, Vol.117 (26)
Main Authors: Chiu, P.-Y., Lidsky, D., Chuang, Y., Su, Y.-H., Li, J.-Y., Harris, C. T., Lu, T. M.
Format: Article
Language:English
Subjects:
Applied physics
Carrier density
Construction materials
Dopants
Doping
Field effect transistors
Fluence
Germanium
Heterostructures
Ion implantation
Modulation
Modulation doping
Quantum wells
Semiconductor devices
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Summary: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.
ISSN:0003-6951
1077-3118
DOI:10.1063/5.0031992