In this work we study device-relevant issues, such as doping efficiency and
thermal stability, of recently proposed intrinsic modulation doping approa
ch where intrinsic defects (P-In antisites) are used as a carrier source in
stead of impurity dopants. The InP/InGaAs heterostructure designed to resem
ble high electron mobility transistor (HEMT) structures, where all the laye
rs were grown at a normal growth temperature 480 degrees C except for the t
op InP layer which was grown at 265 degrees C, was used as a prototype devi
ce. A comparison between the intrinsically doped structure with extrinsical
ly doped HEMTs, which have an identical design except that the top InP laye
r was instead Si-doped and was grown at 480 degrees C, reveals a high effic
iency of the intrinsic doping. The thermal stability of the intrinsically d
oped HEMT is examined by annealing at temperatures 400-500 degrees C releva
nt to possible processing steps needed in device fabrication. The observed
severe reduction of the carrier concentration after annealing performed wit
hout phosphorous gas protection is attributed to the known instability of a
n InP surface at T > 400 degrees C. Thermal stability of the intrinsically
doped HEMT is shown to be improved by using an InP cap layer grown at 480 d
egrees C. (C) 1999 Elsevier Science B.V. All rights reserved.