Oxygen incorporation in AllnP, and its effect on P-type doping with magnesium

Abstract

Oxygen incorporation in Al y In 1-y P (y ~ 0.5) grown by metalorganic chemical vapor deposition (MOCVD) has been studied as a function of PH 3 flow, growth temperature, and alloy composition. Both O 2 and diethylaluminum ethoxide (DEAlO) were employed as sources of oxygen. The incorporation of oxygen was found to be a superlinear function of O 2 or DEAlO flow. When multiple sources of oxygen are present, a surface interaction leads to enhanced oxygen incorporation. Oxygen incorporation cannot be adequately described by a simple dependence on growth temperature or V/III ratio due to strong interactions between these variables. In Mg-doped AlInP co-doped with oxygen, the incorporation of both Mg and O is strongly affected by an interaction between the two species, and roughly 10% of the oxygen atoms act as compensating donors.

Donor-acceptor interactions in Al0.5In0.5P

“…Thus, any growth parameters or impurity species that alter donor or acceptor incorporation or diffusion properties may have important implications on device design, and it is, therefore, important to thoroughly understand such effects. With regard to such properties, we have previously demonstrated that the deep donor, oxygen, enhances Mg incorporation in Al 0.5 In 0.5 P. 3 Similar to our previous observations regarding Mg-oxygen interactions in Al 0.5 In 0.5 P, various other research groups have reported that shallow-donor species, such as S or Si, have enhanced acceptor incorporation in III-V semiconductors. [4][5][6][7][8][9][10][11][12][13] In addition to enhancing acceptor incorporation, such shallow-donor species have also been shown to suppress acceptor diffusion in III-V semiconductors, [4][5][6][7][8][9][10][11][12][13] thus providing motivation to investigate the potential impact of the deep donor, oxygen, on Mg diffusion in Al 0.5 In 0.5 P. In addition to this investigation of Mg-oxygen dopant interactions in Al 0.5 In 0.5 P, we also consider donor-acceptor interactions between Mg and the shallow donors, Te, S, and Si, to allow the reader to more effectively compare our results on Mg-oxygen dopant interactions to previous reports on dopant interactions between shallow donors and Zn or Mg acceptors.…”

“…The lack of such narrow Mg spikes in the oxygen-counterdoped regions A and C of Fig. 2 indicates that electrical compensation is probably not a significant factor in the effect of oxygen on Mg diffusion in Al 0.5 In 0.5 P. In fact, previous studies of oxygen electrical activity in Al 0.5 In 0.5 P suggest that only ϳ10-30% of the oxygen is electrically active, while the remaining oxygen atoms do not compensate acceptors in Al 0.5 In 0.5 P. 3,26 Yet, a third type of donor-acceptor interaction is illustrated in Fig. 6 for the Si-counterdoped sample where Si appears to have a transient-like effect on Mg incorporation at locations where the Si 2 H 6 flow was turned on or off.…”

“…Additional details regarding sample growth conditions are provided elsewhere. 3,16 While this paper focuses on dopant interactions in Al 0.5 In 0.5 P, this work was part of a much broader effort to improve the understanding and control of acceptor diffusion and segregation in the p-type regions of III-V heterostructures. 3,[17][18][19][20] Since the acceptor species was thus the dopant of primary concern, we refer to the acceptor species (Mg) as the dopant species throughout this paper, and we refer to the various donor species as counterdopants.…”

“…That is, they all enhance Mg incorporation and suppress Mg diffusion in Al 0.5 In 0.5 P. The effects of each of these donor species on Mg incorporation can be more easily compared by integrating the Mg sheet concentration throughout each of the regions A, B, C, and D, as we have previously done for Mg-oxygen dopant interactions. 3 The results of this comparison, which are presented in Table I, indicate that each of these donor species has a similar affect on Mg incorporation, with the respective Mg-incorporation enhancement ranging from a minimum of ϳ13% for the Si-counterdoped sample (sample 6, [Si] ϳ3 ϫ 10 17 cm Ϫ3 ) to a maximum ϳ50-61% for the Te-counterdoped samples (samples 3 and 4, [Te] ϳ8-9 ϫ 10 17 cm Ϫ3 ). In fact, Table I indicates that the amount of Mg-incorporation enhancement increases with increasing donor concentration, thus suggesting that donor concentration may be more important than donor species in determining the extent of this Mg-incorporation enhancement.…”

Optical conductivity of highly mismatched GaP alloys

“…It has been reported experimentally for AlGaInP that the co-doping of Mg enhances the incorporation efficiency of O and vice versa. 20 In addition to single-photon transitions shown in Fig. 1(b), there are two-photon processes consisting of valence-band-to-IB and IB-to-conduction-band transitions, both of which are optically active.…”