Abstract
We present a gate-recess structure for 0.1 μm metamorphic high-electron-mobility transistors to enhance the maximum frequency of oscillation (fmax). Among the established gate-recess structures, the narrow gate-recess structure shows a degraded fmax, despite superior dc characteristics due to a large gate-to-drain capacitance (Cgd) caused by a small effective gate-to-drain spacing, while the wide gate-recess structure exhibits lower dc characteristics due to the surface effects. To minimize Cgd and maintain the dc characteristics of the narrow gate-recess structure, an additional gate-recess is performed for an electrical isolation between the drain side cap layer and drain electrode. We obtain almost the same extrinsic transconductance of ∼600 mSmm from this, while we achieve ∼18% enhancement of fmax (∼317 GHz) due to ∼16% reduction of Cgd by the increase of effective gate-to-drain spacing compared to the narrow gate-recess structure.
Original language | English |
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Pages (from-to) | H987-H990 |
Journal | Journal of the Electrochemical Society |
Volume | 155 |
Issue number | 12 |
DOIs | |
State | Published - 2008 |