Jin, Chong (2015)
GaN Schottky diodes for signal generation and control.
Technische Universität Darmstadt
Ph.D. Thesis, Primary publication
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Item Type: | Ph.D. Thesis | ||||
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Type of entry: | Primary publication | ||||
Title: | GaN Schottky diodes for signal generation and control | ||||
Language: | English | ||||
Referees: | Pavlidis, Prof. Dr. Dimitris ; Preu, Prof. Dr. Sascha | ||||
Date: | 22 December 2015 | ||||
Place of Publication: | Darmstadt | ||||
Date of oral examination: | 7 November 2014 | ||||
Abstract: | The aim of this work is to explore the potential of GaN Schottky diodes for high fre- quency signal generation and control, with emphasis on their power handling capability. GaN Schottky diodes are expected to provide superior power handling capability due to the wide band-gap of GaN. Theoretical analysis has been performed analytically and numerically. Devices have been fabricated and their performance has been evaluated experimentally. Demonstration of monolithic integrated circuits utilizing the realized devices was also made. The diode figure of merits e.g. Cj0, Rs , Vbr , have been considered with respect to power handling and harmonic generation to permit evaluation of the diode design requirements for satisfying specific circuit needs. Numerical simulation allowed the prediction of device performance for specific geometry and material properties. Simulation results have shown that GaN Schottky diodes have a power handling capability at least 2 times higher than their GaAs counterparts, while maintaining acceptable losses. Several fabrication technology approaches have been studied and implemented for real- izing GaN-based Schottky diodes. Their key steps include dry etching, metal contacts, as well as interconnects. The surface treatment before metal deposition necessary for good quality Schottky contacts has been thoroughly studied. Three means of intercon- nect methods were demonstrated for on-wafer tests. They allowed rapid evaluation of the electrical characteristics of the diodes and set up the basis for the development of monolithic integrated circuits. High frequency small-signal measurements have been performed for the GaN Schot- tky diodes. The obtained S-parameters were used to extract equivalent circuit models. A parameter extraction procedure was established to de-embed the pad parasitics, and obtaining information about their intrinsic elements permitting in this way diode opti- mization. The large-signal characteristics of the fabricated diodes were measured on-wafer using a large-signal network analyzer. This novel characterization method provided immediate information about diode features such as power handling, loss etc. The time-domain waveforms of the diodes were obtained under various operating conditions allowing a better insight into the diode operation. Large-signal models of the diodes have been obtained by considering the extracted small- signal equivalent circuit characteristics and the large-signal measurement results. GaN- based circuits using diodes have been studied. They include a frequency doubler and an analog phase shifter. Consideration of their large-signal characteristics was possible using the extracted diode large-signal models. Doublers made with this technology are expected to provide an output power of 10 dBm at 94 GHz. MMIC phase shifters were designed, fabricated and characterized. They showed a phase tuning (∆φ) of 45◦ and 6-7 dB insertion loss in the 32-38 GHz range. |
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URN: | urn:nbn:de:tuda-tuprints-52126 | ||||
Classification DDC: | 600 Technology, medicine, applied sciences > 620 Engineering and machine engineering | ||||
Divisions: | 18 Department of Electrical Engineering and Information Technology > Höchstfrequenzelektronik | ||||
Date Deposited: | 22 Dec 2015 13:53 | ||||
Last Modified: | 25 Jan 2024 10:53 | ||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/5212 | ||||
PPN: | 386811296 | ||||
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