| dc.description.abstract | Since low-power consumption and high performance are required in the integrated circuits, Sb-based materials are considered to be high potential candidates in high speed electronic device applications, due to the InAs and InGaSb showing highest carrier mobility properties among III-V compound semiconductors. Among a number of high-k dielectric materials, Al2O3 become one of the candidates for high dielectric constant materials used for most electronics. The major reasons are that Al2O3 shows a large dielectric constant, a large bandgap, a high breakdown field, a good thermal stability, and amorphous type of crystal structure. Therefore, in this thesis, the high dielectric constant material of Al2O3 had been used as gate dielectric to develope the Sb-based metal-insulator-semiconductor heterojunction field effect transistors (MIS-HFETs) with in-depth analysis and discussion.
We first analyzed physical and optical properties of the Al2O3 thin film deposited by atomic layer deposition. The physical properties analysis included film thickness, surface roughness and the optical properties by ellipsometer. The various surface treatments of InAs substrate using different chemical solutions were studied in order to investigate the properties of the InAs MOS capacitors. The electrical property characteristics included C-V, I-V and J-E measurements were characterized to obtain the optimum conditions of Al2O3 film for MIS-HFET application. Finally, we fabricated MIS-HFETs using the Al2O3 deposited by ALD as gate dielectric on the conventional InAs/AlSb and InGaSb/AlSb HFET epitaxy materials. The fabricated InAs/AlSb n-channel MIS-HFET with a gate length of 2 μm, demonstrated the maximum drain current (IDSS) of 371 mA/mm, a transconductance (Gm) of 604 mS/mm, and a subthreshold slope is 137 mV/dec, and a peak current gain cut-off frequency (fT) of 10.6 GHz. The InGaSb/AlSb p-channel MIS-HFET with 1μm gate length showed, the maximum drain current of 31 mA/mm, transconductance of 43 mS/mm, and the subthreshold slope of 153 mV/dec.
| en_US |