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Characterization and modeling of metal-semiconductor-metal (MSM) GaAs diodes using to evaporate SiO2 and Pd simultaneously as a mixture electrode (called M-MSM diodes) compared with similar to evaporate Pd as the electrode (called Pd-MSM diodes) were reported. The barrier height (φ b) and the Richardson constant (A*) were carried out for the thermionic-emission process to describe well the current transport for Pd-MSM diodes in the consideration of the carrier over the metal-semiconductor barrier. In addition, in the consideration of the carrier over both the metal-semiconductor barrier and the insulator-semiconductor barrier simultaneously, thus the thermionic-emission process can be used to describe well the current transport for M-MSM diodes. Furthermore, in the higher applied voltage, the carrier recombination will be taken into discussion. Besides, a composite-current (CC) model is developed to evidence the concepts. Our calculated results are in good agreement with the experimental ones.

A thermal treatment was employed to improve the DC performances of npn graded-base AlGaN/GaN heterojunction bipolar transistors (HBTs). Such HBTs without the thermal treatment exhibit a higher turn-on voltage of 6.45 V, a lower current gain of 0.84, and a lower collector current of 3.18 × 10 −4 mA at V BE of 4.5 V. The HBTs are examined by thermal treatment with rapid thermal process (RTP) annealing at various times and various temperatures. Experimental results reveal that the HBTs with the thermal treatment exhibit a lowest turn-on voltage of 3.90 V, a highest current gain of 9.55, and highest collector current of 112.2 mA at V BE of 4.5 V. The thermal treatment brings forth the most remarkable improvements for the HBTs when the base parasitical Schottky diodes are modified.

This paper presents a current transport mechanism of Pd metal-semiconductor-metal (MSM) GaAs diodes with a Schottky contact material formed by intentionally mixing SiO2into a Pd metal. The Schottky emission process, where the thermionic emission both over the metal-semiconductor barrier and over the insulator-semiconductor barrier is considered on the carrier transport of a mixed contact of Pd and SiO2(MMO) MSM diodes, is analyzed. The image-force lowering is accounted for. In addition, with the applied voltage increased, the carrier recombination is thus considered. The simulation data are presented to explain the experimental results clearly.

Characterization and modeling analysis on both ideality factor of the collector current ( C ) and the base current ( B ) have higher than the excepted values of 1.0 and 2.0, respectively, for npn AlGaN/ GaN heterojunction bipolar transistors (HBTs) have been reported. We employ the rapid thermal process annealing (RTP-annealing) to modify the base parasitical Schottky diode (called A-HBTs) after the as-deposited Ni/Au bilayers on the base layer for electrode with no annealing (called N-HBTs) to compare with each other. For a HBT operated in Gummel-plot con¯guration, experimental and modeling results indicate that the base parasitical Schottky diode (BPSD) causes the base current (I B ) and collector current (I C ) with high ideality factor and raise the base-emitter voltage (V BE ) to higher operation point, and therefore lead to more power consumption. Furthermore, the extended EbersÀMoll equivalent-circuit model together with the extracted device parameters provided simulated results that were in a good agreement with experimental ones.