Browsing by Author "Zirath, H."

Now showing 1 - 4 of 4

60GHz broadband 0/1-level RF-via interconnect for RF-MEMS packaging
(2007-10-25)
Wu, Wc.
;
Hsu, L. H.
;
Chang, E. Y.
;
Starski, J. P.
;
Zirath, H.
The RF-via interconnect structure front the 0- to the 1-level package for coplanar RF-MEMS devices packaging is evaluated. The 0/1-level interconnect structure was designed and optimised using the electromagnetic simulation tool. The structure was then successfully fabricated and characterised up to 67 GHz. The measured and simulated results show good agreement, demonstrating DC-to-60 GHz broadband interconnect performance through the two levels package with return loss below 15 dB and insertion loss within 0.6 dB.
Coaxial transitions for CPW-to-CPW flip chip interconnects
(2007-08-16)
Wu, W. C.
;
Chang, E. Y.
;
Huang, C. H.
;
Hsu, L. H.
;
Starski, J. P.
A novel coaxial transition for CPW-to-CPW flip chip interconnect is presented and experimentally demonstrated. To realise the coaxial transition on the CPW circuit, benzocyclobutene was used as the interlayer dielectric between the vertical coaxial transition and the CPW circuit. The coaxial interconnect structure was successfully fabricated and RF characterised to 67 GHz. The structure showed excellent interconnect performance from DC up to 55 GHz with low return loss below 20 dB and low insertion loss less than 0.5 dB even when the underfill was applied to the structure.
DC and microwave performance of AlGaN/GaN HEMTs passivated with sputtered SiNx
(2007-07-01)
Shiu, J. Y.
;
Desmaris, V.
;
Rorsman, N.
;
Kumakura, K.
;
Makimoto, T.
The effects of sputtered and room temperature plasma enhanced chemical vapour deposition (RT-PECVD) SiNx passivation on the dc and microwave performance of AlGaN/GaN high electron mobility transistors (HEMTs) are studied. The pulsed I - V characteristics from a class B quiescent bias point and transient measurements indicate that the sputtered SiNx passivation is more efficient in suppressing lag effects in AlGaN/GaN HEMTs. Dispersion-free sputtered SiNx passivated AlGaN/GaN HEMTs were obtained using this technique. Continuous-wave (CW) measurements without active cooling give a maximum output power density of 6.6 W mm(-1) at V-gs=- 4 V, V-ds = 50 V and a maximum power added efficiency of 51.3% at V-gs=- 4 V, V-ds = 30 V at 3 GHz on 2 x 50 mu m AlGaN/GaN HEMTs on the sapphire substrate, with a gate length of 2 mu m and without field-plated gates. To the best of our knowledge, this is the highest level power density reported on the sapphire substrate without field-plate design. The extrinsic cut-off frequency (f(t)) and maximum oscillation frequency (f(max)) are 51 GHz and 100 GHz, respectively, on 2 x 50 x 0.15 mu m HEMTs. To our knowledge, the sputtered SiNx passivation for AlGaN/GaN HEMTs is a unique technique, which has never been published before.
Influence of oxynitride (SiOxNy) passivation on the microwave performance of AlGaN/GaN HEMTs
(2008-05-01)
Desmaris, V.
;
Shiu, J. Y.
;
Rorsman, N.
;
Zirath, H.
;
Chang, E. Y.
The effects of the composition of oxynitride passivations (SiOxNy) deposited by plasma enhanced chemical-vapor deposition (PECVD) at room temperature on the microwave performance of AlGaN/GaN high electron mobility transistors (HEMTs) were investigated. Five different SiOxNy passivating layers were deposited covering the whole range of dielectrics combinations from SiOx to SiNy. Their impacts on the HEMT performance were studied by means of DC, S-parameters, pulsed IV and load-pull measurements. The oxynitride dielectric with a refraction index of 1.58 was shown to be an effective SiOxNy passivation for limiting the gate-lag effects in the HEMTs and at the same time increasing the breakdown voltage of the device. It is thus a promising passivation layer for microwave power high voltage and high power applications. (c) 2007 Elsevier Ltd. All rights reserved.