Transformation behavior of room-temperature-stable metastable defects in hydrogen-implanted n-type silicon studied by isothermal deep-level transient spectroscopy

Isothermal deep-level transient spectroscopy (DLTS) with a single pulse has been used to study the transformation behavior of hydrogen-related metastable defects labeled EM1 (E_c-0.28 eV) and EM2 (E_c-0.37 eV), which are observed in n-type silicon implanted with hydrogen ions at 88 K and subsequently heated to room temperature. EM1 shows the anomalous filling behavior that its isothermal DLTS peak height decreases exponentially with filling pulse duration time in the range from 1 ms to 1000 s. A corresponding exponential increase in EM2 peak height is found. This indicates that EM1 filled with electrons is transformed into EM2 during the application of filling pulse. The dependence of EM1 and EM2 peak heights on the emission time between two adjacent filling pulses reveals the transformation from EM2 to EM1 with fast rates after electron emission of EM2. This shows that EM1 and EM2 are different configurations of the same defect and are stable under reverse bias and zero bias, respectively. The rate equations governing the emission, capture, and transformation kinetics for EM1 and EM2 are solved to extract those parameters. The electron emission rate of EM2 and the transformation rate from EM1 to EM2 are found to be dependent on electric field. It is suggested that the hydrogen-related metastable defect is donorlike.