Abstract
In this letter, we investigated the impact of the source-to-drain spacing (LSD) on the dc and high-frequency characteristics of indium-rich In0.8Ga0.2As/In0.52Al0.48As high-electron mobility transistors (HEMTs) on a 3-in InP substrate. Lg = 87 nm HEMTs with different values of LSD were fabricated ranging from 1.55 to 0.8 μm, and their dc and RF responses were measured and analyzed in detail. In order to suppress the increase of the parasitic gate capacitance, we maintained the gate stem height as high as 200 nm in our device fabrication. Both the maximum transconductance (gmmax) and on-resistance (RON) improved as LSD scaled down to 0.8μm. At the same time, the high-frequency figures of the merit, such as current-gain cutoff frequency (fT) and maximum oscillation frequency (fmax), increased with the reduction of LSD. These improvements are attributed to the reduction of series resistances. In particular, the Lg =87 nm device with an LSD = 0.8 μm exhibited an excellent combination of dc and RF characteristics, such as gmmax = 2.7 mS/μm, RON = 318 Ω μm, fT= 519 GHz, and fmax = 645 GHz, respectively. The results obtained in this letter indicate that the reduction of LSD down to 0.8 μm continues to improve both the dc and RF characteristics of the InGaAs/InAlAs HEMTs, and a possible increase in parasitic capacitance components, associated with a T-shaped, is still negligible in our device architecture.
Original language | English |
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Article number | 8496880 |
Pages (from-to) | 1844-1847 |
Number of pages | 4 |
Journal | IEEE Electron Device Letters |
Volume | 39 |
Issue number | 12 |
DOIs | |
State | Published - Dec 2018 |
Keywords
- current gain cut-off frequency (fT)
- HEMT
- InGaAs
- maximum oscillation frequency (fmax)
- on-resistance
- series-resistance