NEGATIVE-U CENTERS IN 4H SILICON-CARBIDE

Characterization of two negative-U centers in 4H SiC has been performe d using various capacitance transient techniques. Each center gives ri se to one acceptor level (-/0) and one donor level (0/+), where the el ectron ionization energy of the acceptor level is larger than that of the donor level. The two-electron emissions from the two acceptor leve ls give rise to the previously reported deep level transient spectrosc opy peak associated with the so-called Z(1), center. Direct evidence f or the inverted ordering and temperature dependence studies of the ele ctron-capture cross sections of the acceptor levels will be presented. [S0163-1829(98)51140-X].