AlGaN‐based heterostructures grown on 4 inch Si(111) by MOVPE

Abstract

AlGaN is an important material for ultra‐violet light emitters, photo detectors and high breakdown voltage switching devices. In this work, crack‐free AlxGa1‐xN (5% < x < 55%) layers up to 1.5 μm have been grown on 4 inch Si(111) using an AlN/AlyGa1‐yN (y > 70%) template. The structural quality of AlGaN layers is comparable to that of GaN layers grown on silicon(111). For Al0.16Ga0.84N, the FWHM of HR‐XRD (0002) and (‐1102) ω‐scan is around 650 arc sec and 1200 arc sec respectively. Based on this high quality AlGaN buffer, a double heterostructure (DH) FET was demonstrated. The sheet resistance of DH‐FET is 274 ± 4.7 Ω/□ and the uniformity value of 1.7% is also excellent. Some of the wafers have been processed. Devices with a gate length of 2 μm showed current density of 500 mA/mm and transconductance of more than 200 mS/mm. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Growth and characterization of N‐polar GaN and AlGaN/GaN HEMTs on (111) silicon

“…The corresponding values measured for samples with AlGaN buffers where the composition was reduced in steps amounted to 0.16° and 0.2°, most likely because the GaN layer in those samples was considerably thicker, 900 nm, in comparison to 300 nm for the samples with graded AlGaN buffer. The measured XRD data corresponded well to results measured for Ga-polar GaN on Si films using both procedures [3,4].…”

“…A variety of methods were developed to mitigate the lattice mismatch and the large difference in the thermal expansion coefficients between GaN and Si, and GaN based light emitting diodes as well as transistors were demonstrated [1][2][3][4]. Thereby the GaN layers were grown in the typical +c-direction resulting in Ga-polar films.…”

Growth of AlGaN Film on Si (111) Substrate

“…However, for the large lattice mismatch and the large coefficient of thermal-expansion (CTE) mismatch between GaN (AlN) and Si, the growth of high quality, thick crack-free AlGaN on Si substrate is a difficult task, and the cracks and high defect density seriously degrade the performance of GaN based devices on Si substrates. There are few reports on AlGaN growth on silicon substrates [9][10][11]. In this study, the epitaxy of AlGaN on 2 in Si ( 1 11 …”

High breakdown voltage in AlGaN/GaN/AlGaN double heterostructures grown on 4 inch Si substrates

“…It is believed that the improved channel carrier confinement is the key factor for achieving high-power performance. Indeed, the DHFET offers a better confinement of the two-dimensional electron gas (2DEG) and avoids electron spillover to the AlGaN barrier and buffer layers at high power conditions [4]. Also, both the suppression of the buffer leakage current and a high buffer breakdown voltage are important factors to achieve high quality power switching devices.…”

“…The DHFET structures are completed by the growth of a GaN channel, an Al 0.35 Ga 0.65 N Schottky layer and an in-situ grown silicon nitride passivation layer. More details on the actual epitaxial growth can be found in [4]. The total thickness of the buffer layer is 2 µm for sample A and 2.7 µm for sample B.…”