Growth of high quality AlInAs by low pressure organometallic chemical vapor deposition for high speed and optoelectronic device applications

Abstract

In this paper, we report on the low pressure organometallic chemical vapor deposition of AlInAs lattice matched to InP and the effect of the substrate temperature and V/III ratio on the layers grown. High quality AlInAs with X-ray and photoluminescence (5 K) linewidths of 21 arc sec and 15 meV, respectively, was obtained. It is demonstrated that a high growth temperature and a high arsine flow rate are necessary for obtaining good electrical and optical properties. A discrepancy was shown to exist between C-V and Hall derived carrier concentrations probably due to deep levels affecting the C-V measurements and a two-dimensional electron gas (2DEG) at the AlInAs/InP interface affecting the Hall measurements. The existence of a 2DEG at the AlInAs/InP interface, with a sheet density of 2.9×10 11 cm -2 and a mobility of 11050 cm 2/V°s at 4 K, was shown using Shubnikov-De Haas measurements. A correlation was made between oxygen or an oxygen related complex and high C-V measured carrier concentrations and large leakage currents in reverse biased Schottky contacts. An intense emission at ~1.2 eV, present in 5 K photoluminescence spectra of AlInAs/InP, was attributed to a spatially indirect transition across the AlInAs/InP interface. Conduction and valence band offsets of 448.8 and 324.3 meV, respectively, were deduced from the energy of this transition. Self aligned 0.25 μm gate high electron mobility AlInAs/GaInAs transistors with a transconductance as high as 1150 mS/mm and f t = 80 GHz at room temperature were fabricated. Finally, metal-semiconductor-metal photodetectors with a leakage current as low as 5 nA at 5 V, breakdown voltage greater than 25 V, responsivity of 0.42 A/W at 1.3 μm wavelength, and a bandwidth of 8 GHz were demonstrated.