Berlin 2018 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 10: Nitrides: Devices

HL 10.1: Vortrag

Montag, 12. März 2018, 15:00–15:15, EW 203

Mechanism and Reduction of temperature-dependent RF loss of GaN-HEMTs on Silicon substrate — •Tien Tung Luong, Yi Heng Chen, Chung Han Chiang, Yen Teng Ho, Shane Chang, and Edward Yi Chang — National Chiao Tung University, Hsinchu, Republic of China (R.O.C)

Regarding the unique characteristics (high breakdown field, high power density, high efficiency, and broadband); GaN-based HEMTs are able to operate at high power, high frequencies, and high temperatures; exhibiting various excellent characteristics superior to those of conventional Si-based semiconductors. GaN-HEMTs on Si technology is expected to drastically reduce the fabrication cost. Nevertheless, one of the main issues is the parasitic loss that can adversely impact the RF device performances. In order to reduce the loss of RF operation of devices on Si, a high-resistivity (HR) Si substrate is commonly used; however, the RF loss drastically increases at high-junction temperature. A free-electron inversion channel, which is caused by the positive piezoelectric charge at the AlN/Si interface induced by the piezoelectric field in the tensile AlN grown on Si, plays a critical role in the RF losses. Understanding the loss mechanisms of GaN-HEMT on Si will undoubtedly help to design epitaxial growth structure for further improving the overall device RF performance. An adoption of a low-temperature AlN near Si interface induces an unintentionally carbon-doped layer acting as a negatively fixed charge layer that is able to compensate for positive piezoelectric charge resulting in the improvements of both the RF losses and thermal degradation.