This study proposes a post‐distortion linearisation technique for 5 and 60 GHz complementary metal–oxide–semiconductor (CMOS) power amplifiers (PAs). The technique improves the output 1 dB gain compression point (OP1dB) and power‐added efficiency (PAE) of the PA when the lineariser is turned on. The 5 GHz PA that is fabricated in tsmcTM 0.18 μm CMOS achieves a 16.3 dB gain, a 20 dBm OP1dB and a 32.6% PAE. The linearised 5 GHz PA improves the OP1dB and PAE by 2.3 dB and 3.2% as compared to the PA without lineariser. The difference between the OP1dB and saturated power (Psat) is <0.2 dB. The 60 GHz PA was implemented in a 90 nm CMOS process with a chip area of 0.57 mm2. The PA achieves a 14.8 dB gain, a 16.8 dBm OP1dB with a 16.3% PAE and a 15 GHz 3 dB bandwidth. The power difference between the OP1dB and Psat is <0.3 dB. The linearised 60 GHz PA improves the OP1dB and PAE by 3.2 dB and 5.8% as compared to the PA without lineariser.
In this report, a delta-doped triple-barrier regenerative switching device is studied. The device is composed of a p+-n junction in series with a triple-barrier unipolar diode. One barrier is induced by a δn+-i-δp+-i-δn+ structure. The gate electrode is placed on the two barriers near the substrate. Three-terminal voltage-controlled and current-controlled current-voltage characteristics are shown. The ratio V
S/V
H of switching to holding voltage is more than 3 under bias. At positive gate-to-cathode (GC) bias, the switching voltage decreases with the increase of gate bias and then saturates to some value when the bias is more than 0.5 V. The switching phenomena still appear at high positive GC bias. At negative GC bias, holes, trapped in the potential well of holes, are from diffusion current or generated by avalanche breakdown.
This paper focuses on implementing two novel CMOS-MEMS type switches: buckling type and thermal type, by using commercially available TSMC 0.35 μm two-poly four-metal (2P4M) CMOS process. There are two novel designs in these two type switches: first, the soft contact structure with post-processing fabrication; second, using residual stress to achieve large structural deformation in buckling type and thermal type switches. To create the soft contact structure, residual gradient stress effect has been utilized to make bending-down curvatures. According to the experiments, the layer Metal1 has the largest negative residual gradient stress [1] effect that can achieve the largest negative deflection in z-axis. Because the structure will bend down after post-processing release, larger lateral contact area are set up to gain the lower contact miss ability. In the post-processing fabrication, 0.3μm thickness gold will be deposited on the contact tips. Due to the essence of gold, comparing with aluminum, has no oxidation issue, gold also has the advantage of higher conductivity to reduce the electrical power loss. In the buckling type design, the switch uses residual stress to achieve lateral buckling effect to solve long distance problem. In the thermal type design, this paper design a folded-flexure [2, 3] with the electro-thermal excitation to turn the switch on or off. In the prototype, the device size is 500 μm × 400 μm and the gap between two contact pads is 9 μm in offstate. on the experimental results, the switch can work stably at 3 volts, and the displacement of the thermal type switch can achieve 2.7μm, which is sufficient for the mechanism of switching-on or switching-off.
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