0.1 μm enhancement-mode pseudomorphic InGaAs/InAlAs/InP HEMT

Enhancement-Mode High Electron Mobility Transistors Lattice-Matched to InP Substrates Utilizing Ti/Pt/Au Metallization

“…Buried-Pt gates have been utilized to achieve high Schottky barrier height, B , as well as to reduce d d . 1,3,5,6) Strained In 0:45 Al 0:55 As/In 0:75 Ga 025 As heterostructures have also been employed to achieve high barrier height with Ti/Pt/Au gate metallization, because B is the higher for In x Al 1Àx As with higher Al content. 6) In the present study, the thickness of heterostructures has been scaled down (d d scaling) to achieve positive threshold voltage, utilizing Ti/Pt/Au metallization, which has better reliability performance than the buried-Pt gate although its barrier height, B , is lower than that of buried-Pt gates.…”

“…It has been reported that thermal annealing of gate metallization increased the Schottky barrier height of the gate metal and reduced the effective Schottky layer thickness. 1,3,5) Schottky barrier height enhancement induces threshold voltage shift without changing the peak transconductance value, whereas, gate metal diffusion into the semiconductor layer results in the enhancement of peak transconductance values as well as threshold voltage shift. Compared with Pt/Ti/Pt/Au gate metallization, Ti/Pt/Au metallization resulted in a smaller threshold voltage shift and a smaller increase in transconductance, which indicate that the penetration depth of Ti is less than that of Pt and the enhancement of the Schottky barrier height is also less with Ti/Pt/Au metallization.…”

“…Enhancement-mode high electron mobility transistor (EHEMT) technology has various advantages over depletion-mode HEMT (DHEMT) technology, such as excellent power-added efficiency (PAE) and low voltage operation leading to low power consumption. 1) GaAs-based enhancement-mode field effect transistors (FETs) have an important application in commercial power amplifiers for wireless handsets. 2) EHEMTs based on In 0:52 Al 0:48 As/In 0:53 Ga 0:47 As heterostructures have been monolithically integrated with depletion-mode HEMTs (DHEMTs) to construct high-speed digital circuits 3,4) on InP and GaAs substrates.…”

“…Buried-Pt gates have conventionally been utilized to realize EHEMTs on InP substrates. 1,3,5) However, there are potential problems with this technology. [6][7][8] The reliability of Pt-based gates on InAlAs under elevated temperatures is problematic due to the continuous shift of threshold voltages of HEMTs induced by the diffusion properties of Pt into the InAlAs Schottky layer.…”

Enhancement-mode In0.52Al0.48As∕In0.53Ga0.47As∕InP HEMT utilising Ir∕Ti∕Pt∕Au gate

“…Introduction: Thermally-treated Pt-based metallisation is commonly utilised as the Schottky gate contact in enhancement-mode InAlAs= InGaAs high electron mobility transistors (eHEMTs) owing to its high Schottky barrier height [1][2][3][4][5]. However, the rapid diffusion of Pt in InAlAs has constituted a reliability issue [6] since it alters crucial device parameters such as transconductance, threshold voltage, and gate capacitance.…”