We present experimental and theoretical proof for a single and unique relationship between the breakdown voltage and power efficiency of visible light emitting devices fabricated in standard BiCMOS processes.

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We measure the contact resistance and 1/f noise on n-type GaN samples grown by various vapour phase epitaxy (VPE) technologies. Contacts are made in a linear transmission line geometry (TLM). In some samples the metal semiconductor contact noise dominates. This 1/f noise spans over 4 decades. In other samples the bulk noise dominates. This 1/f noise is described by the empirical relation S R /R 2 =α/Nf.

We present radio-frequency (RF) power results of GaN-based high electron mobility transistors (HEMTs) with total gate widths (W g ) up to 1 mm. The AlGaN/GaN epi-structures are MOVPE-grown on 2-inches semi-insulating (s.i.) 4H-silicon carbide substrates. The HEMTs have been fabricated using an optimized process flow comprising a low-power Ar-based plasma after ohmic contact metallization, cleaning of the AlGaN surface prior to the Schottky gate metallization using a diluted ammonia (NH 4 OH) solution, and passivation of the AlGaN surface using a silicon nitride layer deposited by plasma enhanced chemical vapor deposition. We will show that the best RF power performance has been achieved by HEMTs with iron-doped GaN buffer layers (GaN:Fe). Devices with a total gate width of 1 mm yielded a maximum output power of 11.9 W at S-band (2 -4 GHz) under class AB bias conditions (V DS = 40 -60 V, and V GS = -4.65 --4.0 V).

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