Cyclotron resonance in space charge layers on si*

Cyclotron resonance of electrons bound in quantized states in space charge layers on a (100) surface of Si has been observed. We have seen the electron resonance in both inversion¹⁾ and accumulation layers. For the case of inversion the cyclotron mass m_c* is found to differ substan-tially from the bulk value 0.1905 m₀ and to vary with the surface density of electrons (Q_s). We find m_c* = 0.230 m_o for Q_s ≈ 0.2 × 10¹² electrons/cm², which decreases to m_c* = 0.208 m_o for Q_s ≈ 2.0 × 10¹² electrons/cm². The relaxation time from cyclotron resonance exhibits a maximum near Q_s ≈ 0.8 x 10¹² electrons/cm² for the inversion layer. In recent work* we have discovered in addition to the fundamental resonance an approximately subharmonic sequence of peaks, which we attribute to cyclotron resonance perturbed by charged trap states at the Si-SiO₂ interface. We also find cyclotron resonance of electrons in an accumulation layer on w-type (100) Si with ipass m_c* close to the bulk value.