High current density contacts for photoconductive semiconductor switches

Technical Report · Sun Aug 01 04:00:00 EDT 1993

DOI:https://doi.org/10.2172/10181185· OSTI ID:10181185

Baca, A G; Hjalmarson, H P; Loubriel, G M; McLaughlin, D L; Zutavern, F J

The current densities implied by current filaments in GaAs photoconductive semiconductor switches (PCSS) are in excess of 1 MA/cm{sup 2}. As the lateral switches are tested repeatedly, damage accumulates at the contacts until electrical breakdown occurs across the surface of the insulating region. In order to improve the switch lifetime, the incorporation of n- and p-type ohmic contacts in lateral switches as well as surface geometry modifications have been investigated. By using p-type AuBe ohmic contacts at the anode and n-type AuGe ohmic contacts at the cathode, contact lifetime improvements of 5--10x were observed compared to switches with n-type contacts at both anode and cathode. Failure analysis on samples operated for 1--1,000 shots show that extensive damage still exists for at least one contact on all switches observed and that temperatures approaching 500{degrees}C are can be reached. However, the n-type AuGe cathode is often found to have no damage observable by scanning electron microscopy (SEM). The observed patterns of contact degradation indicate directions for future contact improvements in lateral switches.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 10181185
• Report Number(s): SAND--93-1474C; CONF-930616--22; ON: DE93018837
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603
42 ENGINEERING
426000
BERYLLIUM ALLOYS
BREAKDOWN
COMPONENTS
ELECTRON DEVICES AND CIRCUITS
CURRENT DENSITY
DAMAGE
ELECTRIC CONTACTS
EXPERIMENTAL DATA
FAILURES
FILAMENTS
GERMANIUM ALLOYS
GOLD ALLOYS
MECHANICAL PROPERTIES
PHOTOCONDUCTIVITY
SCANNING ELECTRON MICROSCOPY
SEMICONDUCTOR SWITCHES
SERVICE LIFE
TEMPERATURE DEPENDENCE