Search

Results are presented of an electron spin resonance (ESR) study carried out at cryogenic temperatures (4.2 K≲T≲35 K) at X‐ and K‐band frequencies of spin‐active defect centers created by ion implantation of 1014 As+ cm−2 at 60 or 80 keV into the SiO2 layer of Si‐SiO2 structures (dSiO2=104–130 nm). Observations were made on single‐crystal boron doped (001) Si wafers of resistivities ρ300 K=0.23 and 22 Ω cm, which had been thermally oxidized. In general, three well‐distinguished centers are observed; two signals, which originate from centers residing in the SiO2 layer, showed typical ‘‘glass’’ pattern line shapes. The first is definitely proven to be the E′ center, which constitutes the first clear experimental evidence of the E′ center in ion‐implanted Si/SiO2 structures. The second signal is shown to correspond very nearly with the ‘‘wet’’ oxygen‐related hole center (OHC) with zero crossing of the derivative spectrum dP/dB given by ga=2.0095. A third previously unreported anisotropic center located at the...

The special features of this spectrometer are square wave frequency modulation and thermal detection. The modulation results from switching the microwave source between two eigenfrequencies of the cavity, obtaining pulsed frequency modulation without amplitude modulation in the microwave field. This technique is in many respects superior to the conventional static field modulation and has comparable noise suppression. The thermal detection is based on resistance modulation of a silicon monocrystal plate in contact with the sample and constitutes a very sensitive detection method at low temperatures.