GaN microwave power FET nonlinear modelling techniques

Brooks, Clive Raymond (2010-03)

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.

Thesis

ENGLISH ABSTRACT: The main focus of this thesis is to document the formulation, extraction and validation of nonlinear models for the on-wafer gallium nitride (GaN) high-electron mobility (HEMT) devices manufactured at the Interuniversity Microelectronics Centre (IMEC) in Leuven, Belgium. GaN semiconductor technology is fast emerging and it is expected that these devices will play an important role in RF and microwave power amplifier applications. One of the main advantages of the new GaN semiconductor technology is that it combines a very wide band-gap with high electron mobility, which amounts to higher levels of gain at very high frequencies. HEMT devices based on GaN, is a fairly new technology and not many nonlinear models have been proposed in literature. This thesis details the design of hardware and software used in the development of the nonlinear models. An intermodulation distortion (IMD) measurement setup was developed to measure the second and higher-order derivative of the nonlinear drain current. The derivatives are extracted directly from measurements and are required to improve the nonlinear model IMD predictions. Nonlinear model extraction software was developed to automate the modelling process, which was fundamental in the nonlinear model investigation. The models are implemented in Agilent’s Advanced Design System (ADS) and it is shown that the models are capable of accurately predicting the measured S-parameters, large-signal singletone and two-tone behaviour of the GaN devices.

AFRIKAANSE OPSOMMING: Die hoofdoel van hierdie tesis is om die formulering, ontrekking en validasie van nie-lineêre modelle vir onverpakte gallium nitraat (GaN) hoë-elektronmobilisering transistors (HEMTs) te dokumenteer. Die transistors is vervaaardig by die Interuniversity Microelectronics Centre (IMEC) in Leuven, België. GaN-halfgeleier tegnologie is besig om vinnig veld te wen en daar word voorspel dat hierdie transistors ʼn belangrike rol gaan speel in RF en mikrogolf kragversterker toepassings. Een van die hoof voordele van die nuwe GaN-halfgeleier tegnologie is dat dit 'n baie wyd band-gaping het met hoë-elektronmobilisering, wat lei tot hoë aanwins by mikrogolf frekwensies. GaN HEMTs is 'n redelik nuwe tegnologie en nie baie nie-lineêre modelle is al voorgestel in literatuur nie. Hierdie tesis ondersoek die ontwerp van die hardeware en sagteware soos gebruik in die ontwikkeling van nie-lineêre modelle. 'n Intermodulasie distorsie-opstelling (IMD-opstelling) is ontwikkel vir die meting van die tweede en hoër orde afgeleides van die nie-lineêre stroom. Die afgeleides is direk uit die metings onttrek en moet die nie-lineêre IMD-voorspellings te verbeter. Nie-lineêre onttrekking sagteware is ontwikkel om die modellerings proses te outomatiseer. Die modelle word geïmplementeer in Agilent se Advanced Design System (ADS) en bewys dat die modelle in staat is om akkurate afgemete S-parameters, grootsein enkeltoon en tweetoon gedrag van die GaN-transistors te kan voorspel.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/4306
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