Minority carrier lifetime and radiation damage coefficients of germanium

We report on the measurement of minority carrier lifetime and on the radiation damage resistance of bulk Ge. Lifetime measurements are performed using the resonance-coupled photoconductive decay (RCPCD) method. Specifically, we examine the dependence of the lifetime as a function of the Ge resistivity and various 1 MeV electron radiation fluences. We measure hole lifetimes ranging from /spl sim/0.9-34 /spl mu/s for n-type Ge samples, corresponding to diffusion lengths of /spl sim/30-400 /spl mu/m. Electron lifetimes in p-type Ge range from /spl sim/0.6-19 /spl mu/s, corresponding to diffusion lengths of /spl sim/30-420 /spl mu/m. Lifetime measurements are also made after exposure to 1 MeV electron fluences ranging from 10/sup 13/ to 10/sup 15/ cm/sup -2/ and these results are used to estimate the minority carrier lifetime and diffusion length damage coefficients K/sub /spl tau// and K/sub L/.