Drift and Conductivity Mobility in Silicon

Abstract

Drift mobility measurements have been made on eleven silicon single crystals ranging in resistivity from 19 to 180 ohm cm. The drift mobility of electrons (${\ensuremath{\mu}}_{n}$) in the purest $p$-type crystals and of holes (${\ensuremath{\mu}}_{p}$) in the purest $n$-type crystals can be expressed by the formulas ${\ensuremath{\mu}}_{n}=(2.1\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{9}{T}^{\ensuremath{-}2.5\ifmmode\pm\else\textpm\fi{}0.1}$ and ${\ensuremath{\mu}}_{p}=(2.3\ifmmode\pm\else\textpm\fi{}0.1)\ifmmode\times\else\texttimes\fi{}{10}^{9}{T}^{\ensuremath{-}2.7\ifmmode\pm\else\textpm\fi{}0.1}$ between 160 and 400\ifmmode^\circ\else\textdegree\fi{}K. At 300\ifmmode^\circ\else\textdegree\fi{}K ${\ensuremath{\mu}}_{n}$ and ${\ensuremath{\mu}}_{p}$ are 1350\ifmmode\pm\else\textpm\fi{}100 and 480\ifmmode\pm\else\textpm\fi{}15 ${\mathrm{cm}}^{2}$ (volt ${\mathrm{s}\mathrm{e}\mathrm{c})}^{\ensuremath{-}1}$, respectively. The conductivity of some of these crystals was measured between 78 and 400\ifmmode^\circ\else\textdegree\fi{}K, and provides independent evidence for the temperature dependences of mobility quoted in the foregoing.Below 100\ifmmode^\circ\else\textdegree\fi{}K hole mobility in the $n$-type crystals decreases markedly, probably at least in part because of short-time trapping of the injected holes.