High Electron Mobility Transistors Yield Improvement with Ultrasonically Assisted Recess for High-Speed Integrated Circuits

Abstract

InAlAs/InGaAs high electron mobility transistors (HEMTs) have been a great contribution to the research and development of high-speed integrated circuits, owing to their high electron mobilities, high saturation velocities, and high sheet electron densities. In integrated circuits using a HEMT as active device, the gate recess process has considerable influence on the yield and uniformity. The wet recess of a 0.1 mm gate footprint has difficulty achieving a high yield greater than 98% due to a nonuniform reaction between the etchant and the semiconductor. A uniform initial reaction between the InGaAs cap layer and the wet etchant mainly determines the yield and uniformity. In this paper, we present an ultrasonically assisted recess method of promoting a uniform initial reaction in the recess process. This method enables us to achieve a high yield and a high uniformity in integrated circuits.

A CPW-Based 77 GHz Power Amplifier with Cascode Structure Using a 130 nm In0.88GaP/In0.4AlAs/In0.4GaAs mHEMTs

“…This structure achieved a sheet carrier density of 3.27×10 12 cm -2 and an electron mobility of 7,490 cm 2 /V-s at 300 K. The 130 nm T-gates were defined by e-beam lithography using a trilayer structure with ZEP/PMGI/ ZEP resist. A ultrasonic-assisted technique was used in a narrow recess, so that high uniformity and yield of devices could be achieved [10], [11] . And then, devices were passivated by using a Si 3 N 4 of 600 Å (Fig.…”

Gate Length Reduction Technology for Pseudomorphic In0.52Al0.48As/In0.7Ga0.3As High Electron Mobility Transistors

“…This method was introduced in a previous study. 5) The gate recess was formed using the citric acid solution with an ultrasonic assist of 5 s and without an ultrasonic assist for the rest of the time. The recess with the ultrasonic assist was formed at 35 kHz and 3.5 W in ultrasonic bath.…”

The Gate Length Reducing Process for Pseudomorphic In0.52Al0.48As/In0.7Ga0.3As HEMTs

“…To solve this problem, ultrasonically assisted recess method was applied to this study. This method was introduced in previous work [5]. The gate recess was formed by the citric acid solution with ultrasonic assist of 5 sec.…”