Speaker
Christian Scharf
(Hamburg University (DE))
Description
Simulations of silicon sensors and extraction of parameters from (edge-)TCT measurements rely on the knowledge of a number of material parameters. One of them is the drift velocity for electrons and holes as function of electric field and temperature in high-purity silicon. So far the information on drift velocities for <100> silicon is quite limited. Therefore, <111> results are typically also used for the analysis of <100> data.
Measurements of the drift velocity of electrons and holes in high purity n- and p-type silicon of <100> orientation are presented. The drift velocity is determined from current transients (TCT) of silicon pad diodes using two different methods: the well-established time-of-flight method and the fit of simulated current transients to measured transients. The measurements cover electric field values between 2.5 kV/cm and 50 kV/cm and temperatures between 233 K and 333 K.
We also introduce a parameterization of the dependence of the drift velocities on electric field and temperature, which differs from the standard one [Jacoboni], and which provides a good description of the literature data and our results.
For both electrons and holes differences of more than 15 % are found between the <100> and literature <111> drift velocities. For electrons, the <100> results reflect previous measurements. However, for holes differences of 5 to 15 % are observed for fields above 10 kV/cm. The use of the results presented will improve the accuracy of simulations and analyses of sensors fabricated with <100> silicon, especially in the high field region.
Author
Christian Scharf
(Hamburg University (DE))
