Fabrication of silicon nitride films for forming dielectric and passivating layers in high-voltage GaN transistors
Keywords:
silicon nitride, GaN transistor, dielectric strength, ICP-CVDAbstract
The development of highly reliable passivation coatings that suppress surface leakage currents is a key challenge for modern gallium nitride (GaN) transistors. A comprehensive study of silicon nitride (SiNx) films synthesised by inductively coupled plasma chemical vapour deposition (ICP-CVD) using a unique elevated pressure regime is described. It is shown that varying the key deposition process parameters makes it possible to effectively control the functional characteristics of the films, such as the refractive index, residual mechanical stress level and dielectric strength. The most significant result is the achievement of a record-high breakdown voltage (> 900 V) in films deposited under the optimal regime and characterised by minimal internal stress, critically important for preventing wafer deformation and element degradation. The obtained data demonstrate the possibility of the targeted synthesis of SiNx dielectric films for integration as highly effective passivating and protective layers in GaN devices, making a significant contribution to enhancing their reliability.
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