Paper 2002-07
TRIBICC (TIME RESOLVED
ION BEAM INDUCED CHARGE COLLECTION ) MEASUREMENT OF MINORITY CARRIER LIFETIME
IN SEMICONDUCTOR POWER DEVICES BY USING GUNN'S THEOREM
Presented at 3rd E-MRS 2001 SPRING MEETING Palais des Congrčs Strasbourg (France) June 2002 and to be published in Appl. Surface Science |
C. Manfredotti*1, F. Fizzotti1, A. Lo Giudice1, M.Jaksic2, Z. Pastuovic2, C. Paolini1, P. Olivero1 and E. Vittone1 |
1 Experimental Physics
Department, University of Torino, Torino, Italy, INFM- National Institute for
the Physics of Matter, UdR Torino University, Torino, Italy 2 Department of
experimental physics, Ruđer Bošković Institute (RBI) , P.O.Box 180,
10002 Zagreb, Croatia |
Keywords: |
Abstract
Ion microbeam techniques
like IBICC (Ion Beam Induced Charge Collection ) are very powerful methods in
order to investigate and to map the transport properties in different
technologically important semiconductors and in particular in materials proposed
for nuclear detection.
TRIBICC represents a
further improvement with respect to more traditional IBICC, since it can supply
not only the charge collection efficiency (and through it data on mobility and
trapping time of carriers in drift regions), but also the time behaviors of
charge collection. For long collection times, this means to gather information
also about diffusion lengths and lifetimes of carriers in the diffusion
regions, which are always present in undepleted electronic devices, in particular
power devices, and which are of paramount importance as inputs for simulation
codes. By TRIBICC, in fact, some difficulties could be avoided in analysis of
data collected in cases when lifetimes and shaping times of electronic chain
are similar, and the sensitivity of the method is worse. In order to suitably
analyze TRIBICC data, a theoretical model should be available: in general,
Ramo’s theorem is used, but its validity in cases when space charge is present
is questionable. A more general and powerful method is presented in this work
by using Gunn’s theorem and a particular formulation of the generation function
in order to solve the adjoint of the continuity equation in the time-dependent
case. An application of this method to a commercial power device is presented
and discussed.