Generation-recombination noise and other features of doped silicon in a wide temperature range
The characteristics of the generation-recombination (g-r) process in silicon are investigated in a temperature range from 25 to 360 K. In the case of shallow donors, it is shown that the free electron density strongly depends on temperature: only 20% of donors are ionized at shallow donor densities of about 1017 cm–3 at liquid nitrogen temperature. The maximum of the variance of generation-recombination noise due to the free electron density fluctuations for a silicon sample with shallow donors strongly increases with donor density and shifts with temperature. It is demonstrated that the relative variance of free electron number fluctuations is always equal to 0.5 at low temperatures. The normalized generation-recombination noise spectra are depicted in a very wide frequency range. There is also a detailed investigation of the generation-recombination noise characteristics of an acceptor-partially compensated silicon sample with two donor levels. In this work, the main focus is on the characteristics of silicon doped by shallow donors as it is extremely widely used.