The Properties of GaInAsSb/GaSb Heterostructure Grown by MOCVD and p-GaInAsSb/n-GaSb Photodiodes
- PDF / 300,115 Bytes
- 6 Pages / 414.72 x 648 pts Page_size
- 98 Downloads / 152 Views
chemical vapor temperature(71K) of the typical PL GaInAsSb layers
are presented showing a p-type background and low hole concentration of 6.5 x 1015 cm-3 . The room temperature performances of the p-GaInAsSb/n-GaSb photodiodes are reported. Its responsivity spectrum is peaked at 2 .2 5gm and cuts off at 1.7gm in the short wavelength and at 2 4
. gtm in the long wavelength, respectively. The room temperature detectivity D* is of I ×
109 cm.Hz1 /2 .W-1 . INTRODUCTION GaxInlixAsl-ySby quaternary alloys lattice matched to GaSb substrates have roomtemperature band gaps that range from 0.73eV to 0.28eV, corresponding to the wavelength range from 1.7gm to 4 .4gm. This range of band-gap energy make GaInAsSb a potentially useful material for optical sources[I-3] and detectors[4, 5] in the 2-4gm wavelength range. Most growth of the GaInAsSb/GaSb heterostructures were performed via liquid phase epitaxy(LPE) technique[6-9]. However, a large miscibility gap exists due to the large difference of lattice constants of the four end binary components(GaAs, InAs, GaSb and InSb). and the miscibility gap in the alloy restricts the range of solid composition which can be grown by LPE, as shown by Nakajima et al. [6]. Recently, the successful growth of GaInAsSb metastable alloys inside the miscibility gap on GaSb substrates using molecular beam epitaxy(MBE)[10] and metalorganic chemical vapor deposition (MOCVD)[ 11, 12] have been reported. In this paper, the MOCVD growth of undoped GaInAsSb/GaSb heterostructures and the characterizations for the electrical and optical properties of the heterostructure are presented. Moreover, the room temperature performances of p+-GaInAsSb/p-GalnAsSb/n-GaSb photodiodes are reported.
31 Mat. Res. Soc. Symp. Proc. Vol. 415 01996 Materials Research Society
EXPERIMENT The MOCVD growth was performed in a horizontal, RF-heated quartz reactor at atmospheric pressure. Trimethylgallium(TMGa), trimethylindium(TMIn), trimethylantimony (TMSb) and 10% arsine(AsH 3) diluted in hydrogen were used as the precursors. TMGa, TMIn and TMSb were held in coolers at temperatures of -12 cc , 15 cc and 0 cc , respectively. The saturated vapors of TMGa, TMIn and TMSb were carried by Pb-diffused pure hydrogen. The substrates used were Te doped n-type GaSb wafers with a net donor concentration of 5 x 1017 cm-3 and Cr doped semi-insulating GaAs wafers, both with orientations 20 off (100) towards . They were cleaned with the conventional chemical methods. The GaSb
substrates were etched by a mixed solution of nitric acid, hydrochloric acid, and acetic acid (14N0 3 : HC1 : CH 3 COOH= I : 10 : 50). The GaAs substrates were etched 'by a standard chemical etching solution (H2 SO4 : H2 0: H2 0 2 = 5 : 1 : 1). Typical growth parameters used in the experiment are listed in table I . Table I . Growth parameters for GaxInI_xAsI_ySby alloys Growth temperature (%c) TMGa flow rate (mol/min)
570 - 640 (2 - 10)x 10-6
TMIn flow rate (mol/min) TMSb flow rate (mol/min)
(2- 5)x 10-6 (9 - 18)x 10-6
AsH 3 flow rate (mol/min)
(1 - 3)x 10-6
Data Loading...
