Comment on ‘‘Spin resonance of inversion-layer electrons in silicon’’

Wallace and Silsbee have recently interpreted the observation of a g=1.9988 signal in B-doped (100)Si/SiO₂ as the direct detection of inversion-layer electrons by electron-spin resonance (ESR)---an assignment mainly based on gate-bias sensitivity of the signal. An alternative interpretation, however, is offered evidencing that the reported signal originates from an inadvertently grown type-reversed Si layer near the interface comprising a high-volume density of shallow donors---a result of the particular sample preparation applied. Such a feature is amply documented in Si/SiO₂ literature and the characteristics of the attendant donor signal are well understood. Excessive line broadening is suggested as the reason why inversion-layer electrons remain as yet undetectable by direct ESR.