Time-Resolved TEM of Transient Effects in Pulse Annealing of Ge and Ge–Te Films

An improved version of time-resolved TEM is described which detects electron pulse-induced phase transitions with a resolution of 3 ns in specimen areas above 0.3 μm Ø. The heating pulse automatically is switched off within 15 ns after the phase transition is detected. Using a train of needle pulses the specimen also may be probed outside or after the heating pulse. The method is applied to pulse annealing of amorphous Ge and Ge0.6Te0.4 films by electron beams depositing ≈ 1 kW/cm2. Formation times of crystals are determined (5 to 10 ns) and fast disintegration and recrystallization is traced. Pronounced thermal aftereffects are observed, triggering even crystallization within several μs after the end of the heating period.