Development of rugged 2 GHz power bars delivering more than 100 W and 60% power added efficiency

Abstract

In this work we systematically study the structural, optical and electrical properties of AlGaN/GaN heterostructures grown by MOCVD 3-inch on SiC substrates Thefinally developed HEMTs demonstrate excellent highvoltage stability, high power performance and large power added efficiencies. For a drain bias of 100 V an output-power-density around 26 W/mm with 25 dB linear gain is obtained. On 36 mm gate width devices an output power beyond 100 W is achieved with a power added efficiency above 60% and a linear gain around 17 dB. Ruggedness on these large devices is proven by successfully passing harsh intentional device mismatch tests during operation at 50 V. Reliability is tested at a drain bias of 50 V. Under DC conditions a drain-current degradation below 20% after 20 years is extrapolated. Under RF stress the observed change in output power is well below 0.1 dB after a test duration of more than 500h

Trade‐offs between performance and reliability in AlGaN/GaN transistors

“…have Al-contents in the 15 to 22% range, passivation B and field plates of 500 nm length. Our power bars have a gate width of 36 mm and are operated at 50 V and an operating frequency of 2.14 GHz under continuouswave conditions [8]. The chips are diced from the wafer and mounted in an industry standard package.…”

AlGaN/GaN epitaxy and technology

“…Dependence of the leakage current density at 50 V drain bias (gate bias 27 V) on two different gate processes "A" and "B". As a result of the homogeneous and reproducible technology large periphery devices (36 mm gate width) were diced from the wafers and packaged in industry-standard ceramic packages [17]. On these devices an output power beyond 125 W is achieved with a PAE above 60% and a linear gain around 16 dB as demonstrated in Fig.…”

Improved properties of high-Al-composition AlGaN/GaN high electron mobility transistor structures with thin GaN cap layers

“…The application of thicker GaN cap layers was limited as the sheet charge density of the 2DEG decreases with increasing GaN cap layer thickness. 24) Thinner cap layers were mainly employed to reduce gate leakage 25) and current collapse. 26) A thin GaN cap layer was also shown to result in smoother surface step edges compared to uncapped samples.…”