Trikon helps ramp III-V manufacturing

Silicon dominates the microelectronics industry in part because it is much easier to handle and process than other semiconductors. It’s abundant, mechanically robust, and self-passivating. Though group III-V materials like GaAs and InP have superior optical properties and higher electron mobility, manufacturing issues have confined them to specialized niches like optoelectronics and RF devices.

The emergence of optical and wireless telecommunications has created substantial market opportunities for these materials. With those opportunities have come demands for high volume manufacturing with high yield and low cost. Equipment suppliers like Trikon Technologies are attempting to use their experience with silicon’s production requirements as leverage in the emerging compound semiconductor equipment market.

As Trikon’s Michelle Bourke explained, the transition from one market to the other is not always straightforward. compound semiconductor devices have unique processing requirements of their own. For example, a heterojunction bipolar transistor (HBT) is a stack of 10-15 layers, each between a few hundred and a few thousand angstroms thick. A typical manufacturing process first deposits the film stack across the entire wafer, then defines individual transistors by etching. To build the resulting high aspect ratio structures, etch systems need to maintain good sidewall profile control, even while etching through a variety of different materials with different etch characteristics.

Mirror and waveguide structures introduce additional complexity, Bourke said. The etch depth is typically 1-10 microns, with as vertical a profile as possible. Roughness of the sidewall and trench floor can lead to inefficient optical propagation.

Trikon claims that its Omega systems, which are available with either an inductively coupled plasma (ICP) or a magnetic zero resonant induction source, can meet the etching requirements of compound semiconductor devices.

The company also offers physical vapor deposition (PVD) systems for optoelectronic device metallization. Historically, manufacturers have evaporated noble metals onto a mask, lifting the mask off to create wiring structures. Evaporation is non-directional, increasing waste and adding to the risk of cross-contamination when different metals are used. Trikon claims that its Sigma PVD systems are a suitable alternative.