ThC4 Growth of InAsP/lnP Heterostructures by Low-Pressure Metalorganic Chemical Vapor

Deposition Using Tertiarybutylarsine C . A. Tran, R. A. Masut*, J. L. Brebner, R. Leonelli, P. Cova

Groupe de Recherche en Physique et Technologie des Couches Minces - Montreal Thin

Ecole Polytechnique de Montreal P.O. Box 6079 ,

MontrBal, QuBbec,

Fax: ( 5 1 4 ) 3 4 0 - 3 2 1 8

Film Group and 1'UniversitB de Montreal S ta t ion "A"

CANADA, H3C 3A7

Tel: (514) 3 4 0 - 4 3 1 0

ABSTRACT

Both InAs/InP and InAs,-,P,/InP (0.1 5 x 5 0 . 3 ) strained quantum wells and superlattices have been prepared by LP-MOCVD using tertiary- butylarsine (TBAs) as a substitute for ASH,. For InAs/InP the lattice mismatch is 3 . 3 9 % which results in a 6 . 7 3 % difference in the lattice parameter growth direction. The growth was carried out in a horizontal LP- MOCVD system at a pressure of 40 Torr and at 6 0 0 ° C . The relatively large cracking efficiency of TBAs resulted in low As/In ratios ( 4 . 3 for InAs/InP structures and from 0.1 to 0 . 6 for InAs,,,P,/InP structures) . Different growth interruption procedures were applied in order to obtain atomically abrupt interfaces. High-resolution X-ray diffraction (HRXRD) and photoluminescence (PL) measurements show that the TBAs-grown material is of high quality, The HRXRD patterns o f single and multiple quantum wells show the interference fringes which strongly depend on the structural parameters of grown structures (Fig. 1). Using growth interruption at interfaces (of the order of seconds) we have observed intense room temperature PL of the InAs/InP single strained quantum wells (SSQW) (see Fig. 2). At room temperature the PL has a FWHM as narrow as 20 meV for the SSQW whose nominal thickness is 3 0 A (6.5 meV at 8K). Narrower wells of nominal thickness 8A show multiple peaks possibly indicating island growth. The intense room temperature PL demonstrates that nonradiative processes are not a necessary consequence of growth interruption. Thus TBAs can be used for the growth of quantum well structures with a very high radiative efficiency. We report also the systematic study of the effect of growth interruption on interface roughness of InAsXP1-,/InP heterostructures. An enhancement of the As content for structures grown OR

InP (001) relative to those simultaneously grown on InP (001) 2" off towards [110] is clearly shown in HRXRD neasurement (see Fig. 3 ) . This suggests that the composition of the ternary is determined by surface diffusion of As.

* Author to whom correspondence should be addressed.

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Fig.1: HRXRD pattern of a 15-period 25A InAs/ 350A JnP multi-quantum wells.

-

1 InAs/tnP n m

c a 300K d .-

: Y

2 z

z i a

z w c

0 1.1 1.2 1.3

PHOTON ENERGY (eV)

Fig.2: Room-temperature PL of two InAs/InP single strained quantum wells of nominal tliicknesses of 30A and 264.

?,+& - - T G - - a - - - 4 e a . . . #...I

Fig.3: HRXRD patterns of a 10-period 50A IaAsl-,P,/125 A InP strained super- lattice grown simultaneously on InP(OO1) with x=0.16 (upper curve) and InP(OO1) 2" off towards [110] with x=O.11 (lower curve)

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