TY - JOUR
T1 - Effects of multigate-feeding structure on the gate resistance and RF characteristics of 0.1-μm metamorphic high electron-mobility transistors
AU - Oh, Jung Hun
AU - Han, Min
AU - Lee, Sang Jin
AU - Jun, Byoung Chul
AU - Moon, Sung Woon
AU - Lee, Jae Seo
AU - Rhee, Jin Koo
AU - Kim, Sam Dong
PY - 2009/1
Y1 - 2009/1
N2 - We investigate the effects of a multigate-feeding structure on the gate resistance (Rg) and RF characteristics of the high electron-mobility transistors (HEMTs). In this structure, the increase of Rg with the gatewidth (W) is minimized; therefore, high maximum frequency of oscillation (fmax) is achieved. Various numbers of gate feedings (Ngf) using the air-bridge interconnections are adopted for fabricating the 0.1-μm depletion-mode metamorphic HEMTs. From these structures, we observe great reduction in with Rg the increase of Ngf , and their relationship is given by Rg ∝ 1/[2·(Ngf-1)] 2, where Ngf=2,3,4,⋯; on the other hand, the effects of Ngf on other small-signal parameters are negligible. Calculated cutoff frequency (fT) and fmax fromthe extracted small-signal parameters all show good agreement with the measurement results.fT is slightly decreased with the increase of Ngf due to the increase of gate-to-source capacitance. fmax is, however, greatly increased with Ngf , and this effect becomes greater at longer total gatewidth (W × number of gate fingers). This is due to the smaller Rg at greater Ngf in the multigate-feeding structure. We propose that this gate-feeding structure provides a very effective way to suppress Rg and maximize fmax for the applications of the HEMTs with long W.
AB - We investigate the effects of a multigate-feeding structure on the gate resistance (Rg) and RF characteristics of the high electron-mobility transistors (HEMTs). In this structure, the increase of Rg with the gatewidth (W) is minimized; therefore, high maximum frequency of oscillation (fmax) is achieved. Various numbers of gate feedings (Ngf) using the air-bridge interconnections are adopted for fabricating the 0.1-μm depletion-mode metamorphic HEMTs. From these structures, we observe great reduction in with Rg the increase of Ngf , and their relationship is given by Rg ∝ 1/[2·(Ngf-1)] 2, where Ngf=2,3,4,⋯; on the other hand, the effects of Ngf on other small-signal parameters are negligible. Calculated cutoff frequency (fT) and fmax fromthe extracted small-signal parameters all show good agreement with the measurement results.fT is slightly decreased with the increase of Ngf due to the increase of gate-to-source capacitance. fmax is, however, greatly increased with Ngf , and this effect becomes greater at longer total gatewidth (W × number of gate fingers). This is due to the smaller Rg at greater Ngf in the multigate-feeding structure. We propose that this gate-feeding structure provides a very effective way to suppress Rg and maximize fmax for the applications of the HEMTs with long W.
KW - Gate resistance
KW - Maximum frequency of oscillation
KW - Multigate-feeding structure
KW - Power high electron-mobility transistor (HEMT)
KW - Small-signal parameter
UR - http://www.scopus.com/inward/record.url?scp=77958090657&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:77958090657
SN - 0018-9480
VL - 57
SP - 1487
EP - 1493
JO - IEEE Transactions on Microwave Theory and Techniques
JF - IEEE Transactions on Microwave Theory and Techniques
IS - 1
M1 - 4912426
ER -