High Electron Mobility Transistors (HEMTs) are among the fastest three terminal devices existing.
They find their application in communication, sensing, and radar, when high output power, high
gain, and low noise properties are required.
This work describes the development and application of
simulation software, namely the two-dimen-
sional device simulator MINIMOS-NT, for heterostructure devices. In a continuous interplay with process development, a number of HEMT technologies from different foundries are modeled. The frequency range of application covers cell phones (900 MHz) up to ultra-high frequency low noise amplifiers (140 GHz). Thereby special emphasis is put on the Ka-frequency band (26.5-40 GHz) in this work. Devices from various AlGaAs/InGaAs/GaAs and InAlAs/InGaAs HEMT technologies can be precisely simulated in a global calibration concept. For high-power HEMTs in the Ka-band simulation of impact ionization and of self-heating is included in the simulations. The results are correlated to three-dimensional thermal chip simulation. Several studies are presented, e.g. in order to predict the mechanisms within recessed devices. Physics based small-signal S-parameters are extracted with MINIMOS-NT in agreement with measurements using a conventional deembedding concept, whereby special emphasis is put on the quantitative understanding of the bias dependence of S-parameters. From a statistical point of view, sensitivity analysis of HEMTs for Millimeter Wave Integrated Circuits (MMIC) at 77 GHz is given. Applying statistical concepts to both simulations and measurements allows for a better understanding of the technologies. InAlAs/InGaAs HEMTs grown on metamorphic buffer on GaAs and on InP substrates are simulated whereby agreement with measurements is obtained. A rigorous material modeling is presented for this materials system including high field effects. It is found that both approaches, the metamorphic and the lattice matched, can be simulated with an identical set of transport parameters being used. For AlGaN/GaN HEMT a set material parameters has been implemented into MINIMOS-NT and simulations are shown in agreement with data from an experimental process. The technologies under investigation are further characterized with a Ka-band load-pull system that is established. A power density of 735 mW/mm at 35 GHz and an overall absolute output power of 352 mW from one transistor was measured on an optimized AlGaAs/InGaAs pseudomorphic HEMT on coplanar waveguide technology. These HEMTs reach up to 26 V breakdown voltage for 200 nm gate length. Several simulation studies highlight the optimization process, and, most important, the sensitivity towards process variations is investigated in order to obtain stable and long term reliable HEMTs.