Measurement of the drift velocities of electrons and holes in high-ohmic <100> silicon

TL;DR

This study measures electron and hole drift velocities in high-purity <100> silicon across various electric fields and temperatures, revealing significant differences from <111> silicon data and providing improved parametrizations for sensor simulations.

Contribution

It provides new measurements of drift velocities in <100> silicon and introduces improved parametrizations that better match existing data, aiding sensor modeling.

Findings

<100> silicon drift velocities differ by over 15% from <111> data.

New parametrizations improve accuracy of drift velocity models.

Results cover electric fields 2.5-50 kV/cm and temperatures 233-333 K.

Abstract

Measurements of the drift velocities of electrons and holes as functions of electric field and temperature in high-purity n- and p-type silicon with <100> orientation are presented. The measurements cover electric field values between 2.5 and 50 kV/cm and temperatures between 233 and 333 K. For both electrons and holes differences of more than 15 % are found between our <100> results and the <111> drift velocities from literature, which are frequently also used for simulating <100> sensors. For electrons, the <100> results agree with previous <100> measurements, however, for holes differences between 5 to 15 % are observed for fields above 10 kV/cm. Combining our results with published data of low-field mobilities, we derive parametrizations of the drift velocities in high-ohmic <100> silicon for electrons and holes for fields between 0 and 50 kV/cm, and temperatures between 233 and 333 K. In addition, new parametrizations for the drift velocities for electrons and holes are introduced, which provide somewhat better descriptions of existing data for <111> silicon, than the standard parametrization.