Feb 20 – 22, 2017
FBK, Trento
Europe/Zurich timezone

Determination of doping profiles using pad diodes and MOSFETs

Feb 20, 2017, 5:30 PM
Aula Grande (FBK, Trento)

Aula Grande

FBK, Trento

Via Santa Croce, 77 38122 Trento ITALY


Joern Schwandt (Hamburg University (DE))


Capacitance-Voltage (C-V) measurements of pad diodes are a standard tool to determine doping profiles and study radiation damage in silicon. Using C-V measurements on pad diodes with different areas we show that guard rings significantly influence the determination of the doping profile and the active diode thickness. Different methods of extracting the doping profile are compared. Correcting for the influence of guard rings is also important, when measurements on radiation-damaged pad diodes are compared to 1-dimensional TCAD simulations. We recommend pad diodes with different areas as test structures for a precise determination of doping profiles and for the study of radiation damage.

Current-Gate Voltage (I$_{ds}$-V$_{ds}$) measurements for different back-side voltages (V$_{bs}$) on n-MOSFETs with and without p-spray implant are used to determine the doping profile, the oxide-charge density and the dependence of the electron mobility on the electric-field at the Si-SiO$_2$interface. Standard methods from electronics are adapted to the high-ohmic silicon used for sensors, and the difficulties of extracting precise doping profiles are discussed. We use TCAD simulations to verify the analysis methods. The results are relevant for understanding and optimising the p-implants used to isolate the n$^+$-implants of n$^+$-p pixel and strip sensors.

TRACK Technology

Primary authors

Joern Schwandt (Hamburg University (DE)) Eckhart Fretwurst (II. Institut fuer Experimentalphysik) Erika Garutti (Hamburg University (DE)) Robert Klanner (Hamburg University (DE)) Ioannis Kopsalis (University of Hamburg) Martin Weberpals (University of Hamburg)

Presentation materials