Roland Friedrich, Haybatolah Khakzar Department of Microelectronics Fachhochschule Esslingen, Robert-Bosch-Str.1 73037 Gvppingen E-mail:


By simulation of the semiconductor characteristics we can get valuable information of their behaviour. For this purpose usually a circuit simulator like SPICE (Simulation Program with Integrated Circuit Emphasis) [Nagel1975] has to be used. Till now SPICE or SPICE-dependant programs use parameters not directly related to physical properties of the semiconductor material. A materials scientist characterizes his semiconductor with properties like band gap, mobility, doping concentration or effective masses of holes or electrons.We have established a program which consists of equations for junction diodes, bipolar transistors and MISFET4s. We have simulated the pn-junction diode, whereas the diode voltage is carried as function of some physical parameters. That means, the diode voltage is documented over carrier mobility, doping concentration, band gap and effective mass of electrons and holes.The behaviour of a MISFET (Metal Insulator Semiconductor Field Effect Transistor) is simulated with the SPICE Level-1 model (Shichman-Hodges model).

We have studied the influence of mobility as well as on the transfer characteristics of a MISFET. The resulting curves show the ID/VDS-characteristic of a MISFET under variation of mobility respective epsilon for a constant gate voltage. In a second approach, the influence of the isolator material and the gate metal was investigated. To study the effect of charges incorporated into the gate isolation layer, we have simulated the changes of the ID/VDS-characteristic with isolator charge or work function difference as parameter.

We have simulated the behaviour of a bipolar transistor to show the dependancy of IC/VCE-curves on carrier mobility and lifetime as well as on doping concentration of base, emitter and collector. Here we have used the simple Ebers-Moll model.Now one is able to study the device's performance under different materials properties. The developed program is useful not only for the materials scientist or device engineer, but also for students to learn the basics of semiconductor materials and devices.


Name: Roland Friedrich
Address: Robert-Bosch-Str.1
D-73037 Goeppingen, Germany

Employer: Fachhochschule Esslingen,
Department of Electronics / Microelectronics

Job duties: System Manager of installed CADENCE DESIGN SOFTWARE
Design, Simulation and Layout of thickfilm hybrids

presently working on thermal simulations for thickfilm hybrids


Studies at Fachhochschule Muenchen and Esslingen,
Bachelor's degree (Dipl.Ing.(FH))
Master's degree from Open University Hagen
(Fernuniversitaet Hagen)

Membership within IEEE Organization