Sundew’s ALD-Cap Replaces Silicon Nitride Passivation In MMICs

Sundew’s ALD-Cap was integrated into the wafer fabrication process in several leading MMIC foundries to provide lower cost environmental protection. The coating eliminates the need for expensive and cumbersome hermetic packaging without an increase in manufacturing cost.

The conventional PECVD silicon nitride passivation layer used in monolithic microwave integrated circuits (MMICs) was substituted with the ALD-Cap coating. As recently reported by Raytheon1 ALD-Cap coated FETs underwent  a benchmark 96 hour Highly Accelerated Stress Test (HAST) at 130oC and 85% relative humidity. These FETs had a much lower failure rate than standard  SiN coated FETs, predicting hundreds of years of reliable performance under worst-case conditions for ALD capped MMICs.

Lower dielectric loading and better FET performance was also reported. The consistency of the deposition process resulted in tighter tolerances on capacitors and less variation in the RF properties of the FETs.


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