Ohmic Contacts for Technology for Frequency Agile Digitally Synthesized Transmitters
Abstract
Ohmic contacts to InAs and InGaAs have been investigated with the objective of providing low contact resistance, good thermal stability, and process compatibility for scaling lnP-based heterojunction bipolar transistors to smaller sizes. For p-type InAs, the combination of modest contact resistance and good thermal stability at 250 0 C was achieved with metallizations that had thin Pd layers deposited first, fol lowed by W or Ti/Pt barrier layers, then Au. For n-type InAs, however, Pd as a first metal layer provided a higher resistance than conventional Ti/Pt/Au contacts. Ohmic contacts to p-type InGaAs were also investigated. An electron-beam evaporated Pd/Ru/Au contact devel. oped at Penn State provided the minimum resistance of all contacts tested as well as good thermal stability at 250 0 C, as demonstrated using contact resistances and cross-sectional transmission electron microscopy. However, Pt/Ti/Pt/Au contacts provided better thermal stability at 350 0 C. Due to the possibility of electrochemically preparing Pd/Ru/Au contacts, they were selected for further study, and electroless depo sition of successive Pd, Ru and Au layers on InGaAs was investigated.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 21, 2007
- Accession Number
- ADA468888
Entities
People
- Suzanne E Mohney
Organizations
- Pennsylvania State University