Introduction
Prominent examples of high frequency devices are high electron mobility transistors (HEMTs) based on GaAs/AlGaAs, InP, or GaN material systems. HEMT devices are fabricated as discrete single devices as well as in microwave monolithic integrated circuits (MMICs). The most critical design feature for achieving good high-frequency performance well above 100 GHz is a low capacitance gate structure, often in the form of a T shape (T gate).
With EBL structuring, low-capacitance T gates can be precisely built with small gate length lg, a critical parameter for high-bandwidth HEMTs. This is where modern EBL systems play a key role, in particular when it comes to sub-100 nm minimum feature size chip manufacturing.
With EBL structuring, low-capacitance T gates can be precisely built with small gate length lg, a critical parameter for high-bandwidth HEMTs. This is where modern EBL systems play a key role, in particular when it comes to sub-100 nm minimum feature size chip manufacturing.
Application
Radio frequency devices / T-Gates /HEMTs
These gate structures are highly critical for achieving good high frequency device performance. With EBL structuring, low-capacitance T gates can be precisely built with small gate length lg, a critical parameter for high-bandwidth HEMTs. While larger structures such as source and drain metal contacts in MMICs or discrete HEMTs can be patterned with standard optical lithography, gate length pattern fidelity and uniformity across the wafer is crucial to guarantee a high wafer yield.
Metalens structure using efficient formula based patterningMetalens structure using efficient formula based patterningMetalens structure using efficien
150 nm gate in PMMA (bi-layer)
Freestanding multi-terminal graphene device M. Kühne, MPI Stuttgart, Germany
Application
III-V / II-VI compound semiconductor device prototyping
Over the years, compound semiconductors have played a key role in driving innovative electronics in segments such as high frequency, high power, photonics, and sensor devices. A major motivation for using compound semiconductors in the industry is their superior material properties compared to Si with respect to thermal, optical, and electrical properties. In addition, these properties can be tailored to specific device performance parameters by utilizing a large variety of different compound semiconductor materials or even varying compositions within specific material systems. Excellent high-resolution and precise pattern placement capabilities of state-of-the-art EBL systems enable high wafer level yields. In combination with high-end laser-interferometer stages RAITH meets the system stability requirements for process uniformity and placement precision.
Metalens structure using efficient formula based patterningMetalens structure using efficient formula based patterningMetalens structure using efficien
150 nm gate in PMMA (bi-layer)
Freestanding multi-terminal graphene device M. Kühne, MPI Stuttgart, Germany