Growth temperature and plasma power effects on N incorporation in InSbN grown by molecular beam epitaxy

Abstract

The band gap bowing effect is a unique property of dilute nitride III-V materials such as GaAsN, InAsN and InSbN, in which the material band gap reduces as N is substituting the group V elements. For InSbN material, substituting a small amount of Sb by N in InSb (less than 1%) could shift the material band gap to the long wavelength infrared band (8-12 µm) [1], which has important applications such as environmental chemical sensors, medical thermal imaging and space communication. Compared to other alloys for similar applications such as InTlSb (Tl 9%) and InSbBi (Bi 5%) [2,3], InSbN has the important advantage of a much lower miscibility gap due to the small amount of N needed. However, one key issue hindering the progress of InSbN material to date is controlling the fraction of N atoms that sit on the Sb lattice sites (N Sb ) [4,5]. As a result, the formation of defect complexes in this material is prevalent [6,7]. These point defects which alter the stoichiometry of the crystalline alloy are likely to affect the operating characteristics of the semiconductor devices significantly [8].To date, not much information is available on MBE growth conditions of InSbN [4,9]. One of the studies which covered the growth temperature from ~330 to 420 °C has shown that most of the N is incorporated as interstitial N-Sb in the high-temperature regime (380-420 °C) and as N Sb in the low-temperature regime (~330 °C) [10]. However, another report from Jefferson et al. [9], which studied the growth temperature from 320-340 °C, indicated the presence of N Sb only at 330 °C. Hence, the extreme sensitivity of the N incorporation in InSbN at the low temperature regime needs to be verified.In this letter, we report a study of N incorporation in InSbN grown at nominal low temperatures from 270 to 330 °C and the radio frequency plasma power from 150 to 180 W. In addition, a combination of the X-ray diffraction (XRD), secondary ion mass spectrometry (SIMS) and channeling nuclear reaction analysis (NRA) techniques is used for the first time to investigate the concentration of N Sb and interstitial N in InSbN.All our samples were grown on n-type epitaxial-ready InSb(001) substrate. The average growth rate in all samples was 0.6 µm/h and the V:III flux ratio used was approximately 2:1. A 150 nm thick InSbN layer was grown on a 0.3 µm thick InSb buffer layer. The nitrogen flow rate Dilute nitride InSbN alloys have been grown using radio frequency plasma-assisted molecular beam epitaxy. The effects of low growth temperature (270-330 °C) and nitrogen plasma power (150-180 W) on the N incorporation were studied. From the X-ray diffraction (XRD), secondary ion mass spectroscopy and the nuclear reaction analysis ( 14 N(d,p 5 ) 15 N), the highest ratio of substitutional N Sb over the undesired interstitial N is yielded at the lower limit of 270 °C. Like N Sb , a large amount of interstitial N-N also contribute to lattice contraction. Increasing the plasma power (180 W) results in a significant increase in interstitial N in [011] direction.

Molecular beam epitaxial growth and characterization of InSb1 − xNx on GaAs for long wavelength infrared applications

“…Hence, N in these layers is estimated to be less than 0.5%, the lowest limit of detection by this simple x-ray analysis due to an inherent large FWHM of 210 arcsec of heterpitaxial layer of InSb on GaAs. Thus, our growth procedure appears to provide a wider growth temperature window in contrast to earlier reports, 18,20 where N incorporation was found to be more strongly influenced by growth temperature.…”

“…In the past decade, the focus has been to increase N incorporation in the InSb material system, while minimizing defects in the layer by optimizing the growth conditions, such as growth temperature, N plasma power, substrate bias voltage, Sb/In flux ratio for the molecular beam epitaxially (MBE) grown InSbN layers on both InSb 13,14,18 and GaAs [19][20][21] substrates. The nature of N bonding and origin of N-related defects as a function of the growth temperature studied by Pham et al 19 seems to explain the crystal disorder observed in the InSbN material system as reported by Lim et al 19,21 Other studies 7,14,19,21,22 as a function of varying growth parameters suggest lower growth temperatures and low plasma power results in relatively reduced Sb and N induced defects with increased N incorporation.…”

Controlled nitrogen incorporation in GaNSb alloys

“…In addition to Ga(In)NAs, this observation has been made for GaNSb, 10 InNAs, 11 and InNSb. 6,12,13 The N content in GaInNAs alloys grown by Kitatani et al using gas source MBE exhibited an inverse dependence upon the growth rate. 14 15 In these dilute nitride-arsenides, for a fixed flux of N, the N content decreases linearly with increasing growth rate.…”

Dilute nitride InSb<inf>1&#x2212;x</inf>N<inf>x</inf> alloys for mid infrared detection

“…Although InSb 1-x N x /InSb strain-layer superlattice emitters grown by MBE operating at ~10 µm have been reported [7], no LWIR InSb 1-x N x photodetectors have been demonstrated due to the long standing problem of a high background electron concentration [8]. The causes of high electron concentration of ~10 18 cm -3 can be attributed to the existence of charged N interstitials which causes an undesirable blueshift in the measured absorption edge energy [9].…”