Incorporation Of Residual Donor Impurities In High Purity Epitaxial Indium Phosphide

Summary of Donor Peaks in In P Observed by 3 Spectroscopic Techniques (1S-2P) (B=0) D4D3 D5 D4 D3D2(Si) D1(S) MPL (estimated) 000 1 Ili [i Si sx3 x4 x5 X7 LMOS Xo X1 x2 , I 1 x6 I xs 0 0 1 I III I III PT I S 0 0 0 ,I I I I A1 A2 A3 Pl P_2 P3 P4 I I D6 II P5 X9 42 43 44 45 Waven u m ber (cm-1) 46 GS-669 Fig. 3 A summary of spectral peak positions of is -2p transitions for the different donor species in InP as determinedfrom three different spectroscopic techniques PTIS, LMOS,1 and MPL.2 The notations of peak positions inthis figure are the same as in the original reports. 42 / SPIE Vol 1144 Indium Phosphide and Related Materials for Advanced Electronic and Optical Devices (1989) or 5.583, 5.606, and 5.636 meV respectively. From this spectral result at zero magnetic field and the ls-2p (m=-l) transition energies of PI-PS at 6.32T in Fig. 1, the zero field ls-2p transition energies for the additional unidentified donor species, PI and PS, can be accurately determined as 44.869 and 45.956 cm'1 (5.562 and 5.696 meV).Figure 3 gives a summary of ls-2p transition peaks for the different donor species in InP as determined from the above experimental PTIS results measured at B=0 and earlier data from the LMOS 1 and MPL2 studies. In LMOS, measurements Armistead et al.,1 observed the 12 peaks denoted XQ-X9, and Si and S. Dean et al.2» 9 observed 6 peaks labeled Di-D6 for epitaxial samples and later observed additional peaks labeled D^-D^ for bulk materials grown by liquid- encapsulated Czochralski (LEG) techniques. The solid bars in Fig. 3 indicate the donors with positive central cell corrections, while the open bars indicate the donors with negative central cell corrections. The zero field central cell corrections for the different donor species were calculated using the effective mass Rydberg of 7.33 meV.10 Three unusual donor peaks, labeled Ai-A3, which have negative central cell corrections, have been also observed in PTIS spectra of MOCVD InP samples. However, the concentrations of these unknown impurities are insignificant. As shown in Fig. 3, ?2, ?4, and PS are the only donor peaks for which there is agreement with peak positions obtained from all three spectroscopic results. Although the peak position of PI agrees well with X3 of the LMOS result, it does not match any donor detected in the MPL results. It is interesting to note that the peak ?3 is observed only in PTIS, even though it is frequently present in LPE and MOCVD InP samples.The identification of residual donor impurity species corresponding to the spectral peaks has been previously studied using the MPL, LMOS, and PTIS techniques in InP. Intentional doping studies of Si,1 '2, S,1 '2 and Ge1'11 confirm that the PTIS peaks labeled, ?2, ?4, and PS correspond to Si, S, and Ge respectively. A neutron transmutation doping study of InP,12 as well as intentional doping studies with Sn,11 have shown that the PTIS peaks for Sn and S occur at the same energy as P4.3.2 Incorporation of residual donorsThe incorporation behavior of residual donors in InP grown by LPE, PH3-VPE, MOCVD, and MOMBE growth techniques is described below and compared with residual donor incorporation in GaAs grown by the same techniques.