John McGrath

The Fabrication and Market Analysis of Lattice Mismatched Devices

Thesis Abstract
Lattice mismatched semiconductor substrates provide a platform for higher performance semiconductor devices. Through epitaxial growth on GaAs, the lattice constant of the film can be expanded resulting in a desired In_xGa_1-xAs film on which devices can be fabricated. The resulting device exhibits enhanced performance characteristics not achievable on the initial substrate. A self-aligned mesa structure process was developed to fabricate a prototype HBT device utilizing an In_xGa_1-xAs lattice mismatched semiconductor substrate. The self-aligned mesa process eliminated the need for complicated metal etch steps by using a lift-off process and deposited contact metal as an etch mask. Selecting etches that highlight the selectivity of the device layers was critical to the success of the process.

In addition to developing a process to fabricate a device, a market analysis is performed of the possible application space of the technology and derived products. In assessing the feasibility of the possible products, two main areas were addressed, the markets and the competition within each market.

The technology innovation has the ability to attract a variety of markets already served by compound semiconductors. The possible markets and the competition, companies and other materials, already serving the markets are identified and characterized. To determine what markets would be attractive, the full landscape of semiconductor applications is developed. After which we were able to list the specifications and customer needs of each application as well as what materials and what companies were serving these markets. The expected performance for the innovation was then benchmarked against what we projected for the current providers in each application space. Through the benchmarking process we were able to highlight markets in which we had a clear performance and cost advantage. Read More...