n-Type conductivity bound by the growth temperature: the case of Al0.72Ga0.28N highly doped by silicon

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 4; no. 35; pp. 8291 - 8296
• Main Authors: Kakanakova-Georgieva, A, Sahonta, S.-L, Nilsson, D, Trinh, X. T, Son, N. T, Janzén, E, Humphreys, C. J
• Format: Journal Article
• Language: English
• Published: 01.01.2016
• Subjects: Carbon; Electron paramagnetic resonance; Organic chemistry; Precursors; Secondary ion mass spectrometry; Silanes; Silicon; Transmission electron microscopy
• ISSN: 2050-7526; 2050-7534; 2050-7534
• DOI: 10.1039/c6tc02825j

High-Al-content Al x Ga 1− x N layers, x ∼ 0.72, have been grown by metal organic chemical vapour deposition (MOCVD) at a temperature ranging from 1000 to 1100 °C, together with high flow rate of the dopant precursor silane (SiH 4 ) in order to obtain highly Si-doped Al 0.72 Ga 0.28 N layers, ∼1 × 10 19 cm −3 as measured by secondary ion mass spectrometry (SIMS). Further characterization of the layers by capacitance-voltage ( C - V ), electron paramagnetic resonance (EPR), and transmission electron microscopy (TEM) measurements reveals the complex role of growth temperature for the n-type conductivity of high-Al-content Al x Ga 1− x N. While increasing temperature is essential for reducing the incorporation of carbon and oxygen impurities in the layers, it also reduces the amount of silicon incorporated as a donor. While increasing temperature is essential for reducing carbon and oxygen incorporation, it reduces the incorporation of silicon as a donor.