35 nm mHEMT Technology for THz and ultra low noise applications

In this paper we present a very compact 0.28 × 0.55 mm² six-stage terahertz monolithic integrated circuit (TMIC) using 35 nm gate length metamorphic high electron mobility transistors (mHEMTs). A linear gain of 20.3 dB at 610 GHz and more than 18 dB over the bandwidth from 557 to 616 GHz was achieved for a drain voltage V_d of only 0.6 V. The noise performance of the 35 nm mHEMT was investigated on the basis of a packaged H-band amplifier which achieved a small-signal gain of more than 20 dB between 220 and 300 GHz. The averaged measured noise figure was 6.1 dB which is to our knowledge the lowest published value of any MMIC technology in this frequency range. To determine the transistor reliability accelerated lifetime tests in air were done. Based on a 20 % g_{m_max} degradation failure criterion a median time to failure of 1.8 × 10⁵ h at a channel temperature of 75°C and V_DS = 0.8 V was extrapolated