Defect engineering in annealed n-type GaAs epilayers using SiO2/Si3N4 stacking layers

Abstract

We have used SiO2/Si3N4 stacking layers to control the creation of defects in rapid thermally annealed epitaxial GaAs layers. Annealing at 900 °C introduces three electron traps S1 (Ec−0.23 eV), S2 (Ec−0.53 eV), and S4 (Ec−0.74 eV) in SiO2/n-GaAs. The concentrations of S1 and S4 decreased by factors of ∼28 and ∼19, respectively, in Si3N4/SiO2/n-GaAs. The overlap of a hole trap with the S2 peak in Si3N4/SiO2/n-GaAs results in an apparent decrease in the concentration of S2 by over two orders of magnitude. The lower concentration of defects in the region probed by deep level transient spectroscopy is explained by the tensile stress which the Si3N4 layer imposes on the structure during annealing. In addition to S1 and S4, hole traps H1 (Ev+0.28 eV) and H2 (Ev+0.42 eV) are observed in Si3N4/n-GaAs and SiO2/Si3N4/n-GaAs, respectively. The concentration of defects is larger by ∼1.5 times in the latter structure. SiO2/Si3N4 stacking layers can, therefore, be used to achieve spatially selective modification of GaAs-based structures using defect engineering.

Properties of the SiO2- and SiNx-capped GaAs(100) surfaces of GaInAsN/GaAs quantum-well heterostructures studied by photoelectron spectroscopy and photoluminescence

“…2,5 It can be also understood why Ga atoms have stronger tendency to diffuse toward SiO 2 than SiN x films: it is energetically more favourable to form Ga-O than Ga-N. 19 Furthermore, the difference in the thermal expansion coefficients has been shown to affect also the Ga diffusion; namely, SiO 2 has about 10 times larger expansion coefficient than GaAs, whereas for SiN x /GaAs, the difference is clearly smaller. 11,14,17 As 3d spectra (Fig. 4) are similar for all samples, except for as-grown SiO 2 which includes a small As-oxide (þ3.5 eV) emission.…”

“…The previous studies of SiO 2 /and SiN x /GaAs junctions have revealed Ga diffusion into the insulators, [12][13][14] As diffusion into the insulators, 13 As-cluster formation due to nitridation and annealing of GaAs, 15 annealing-induced improvement of the interfaces, 15,16 and defect formation at high-temperature annealings. 17 Recently, it was also reported that pre-treatment of SiO 2 /GaAs interface has an effect on GaInAsN QW photoluminescence (PL) and Ga 3d photoemission, 8 exemplifying the significance of the interface engineering. Yet, the atomic structures of these interfaces as well as changes in them due to the annealing have remained unclear, to large extent because it is not easy to measure the atomic and electronic structures of SiO 2 /and SiN x /GaAs interfaces.…”

Towards a better understanding of the operative mechanisms underlying impurity-free disordering of GaAs: Effect of stress

“…2͑a͒ is in fact a superposition of two discrete defects. 18 A extremely small capture cross section (ϳ10 Ϫ20 cm 2 ) of the dominant of the two defects justifies the unusually long filling pulse width needed for the complete filling of S2*. We have provided a detailed explanation for this difference in an earlier study.…”

Rapid thermally annealed plasma deposited SiNx:H thin films: Application to metal–insulator–semiconductor structures with Si, In0.53Ga0.47As, and InP

“…In the III-V compound semiconductor industry, SiN x :H appears as the most likely candidate as a gate dielectric for metal-insulator-semiconductor field effect transistors ͑MISFETs͒. 8,9 Finally, in the imaging and display technologies, TFTs using SiN x :H gate dielectrics, are already widespread as switching elements in active matrix arrays. 10 SiN x :H thin films can be grown by thermal chemical vapor deposition ͑CVD͒ or by plasma enhanced CVD.…”