Sputter Epitaxy of AlN and GaN on Si(111)

Abstract

Sputter epitaxy is a low‐cost process suited for the deposition of group‐III‐nitride semiconductors and allowing the deposition on large substrate areas at lower growth temperatures than in metal–organic vapor phase epitaxy (MOVPE). High‐quality AlN, AlGaN, and GaN epitaxially grown on Si(111) substrates by reactive magnetron sputtering are demonstrated and details on process parameters are given. With an ammonia‐based reactive sputtering process in a high‐purity environment, AlN can be grown with high crystalline quality comparable to the best MOVPE‐grown samples regarding twist and tilt and with a very low surface roughness, free of the typical columnar structure of sputtered AlN and pits. Also AlGaN, typically required for strain engineering of GaN layers grown on Si, can be grown in the entire compositional range by co‐sputtering of Al and Ga. Thin undoped buffer layer samples show high breakdown field strengths well above 2.5 × 106 V cm−1 and demonstrate the possible use for field effect transistor (FET) buffer layers.

Crack-Free AlN Film Grown on Sputtered-AlN/2D MoS2 Seed Layers on a Si(100)-Based Wafer: Implications for Radio-Frequency Acoustic Filters

“…The value of the mosaicity can be reduced to about 1° when an AlN buffer layer grown by molecular beam epitaxy is inserted between the Si substrate and the sputtered AlN film . Dadgar et al . demonstrate good values of mosaicity, close to 0.3°, for 250 nm AlN films sputtered on Si(111) at 900 °C.…”

III-Nitride Magnetron Sputter Epitaxy on Si: Controlling Morphology, Crystal Quality, and Polarity Using Al Seed Layers

“…The heteroepitaxial growth on cost-effective Si(111) substrates is the preferred choice for power electronic devices; however, GaN-on-Si epitaxy is characterized by large mismatches in lattice parameter and thermal expansion coefficient. High defect densities and cracking of films exceeding 1 μm in thickness are related issues that still need to be solved in the epitaxy process. , A process window for high-quality growth of GaN/AlN by MSE has already been demonstrated. − Careful design of buffer layers and strain management is necessary to successfully grow high-quality and crack-free GaN/AlN on Si. ,, The integration of an Al seed layer into the process flow has proven beneficial to improve the crystal quality of AlN-on-Si grown by various epitaxy technologies. Enhanced surface diffusion and avoiding the formation of SiN x layers promote the adhesion and subsequent growth of AlN layers. − However, a thorough investigation of the impact of this seed layer on the film morphology, structural quality, and film polarity of sputtered GaN/AlN/Si(111) stacks has rarely been reported.…”

Improving Epitaxial Growth of γ‐Al2O3 Films via Sc2O3/Y2O3 Oxide Buffers

“…Si (111) has attracted tremendous attention as a substrate for GaN growth. [3][4][5] However, GaN growth on Si (111) substrate would require an intermediate layer to overcome, meltback etching, lattice and thermal mismatch between GaN and Si which is 17% and 37%, respectively. [6] The use of low-temperature AlN and AlGaN interlayers is established to facilitate thick GaN layer growth on Si.…”