Enhancement of Device Performance in LDMOSFET by Using Dual-Work-Function-Gate Technique

• Published in: IEEE electron device letters Vol. 31; no. 8; pp. 848 - 850
• Main Authors: Ha, Jong-Bong, Kang, Hee-Sung, Baek, Ki-Ju, Lee, Jung-Hee
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.08.2010; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Automotive engineering; Devices; Double-gate FETs; Drains; Driver circuits; Dual-work-function gate (DWG); Electric potential; Flat panel displays; Gates; Intermetallics; lateral double-diffused metal-oxide-semiconductor field-effect transistor (LDMOSFET); mobility; MOSFETs; Nickel; nickel silicide; Performance enhancement; Power dissipation; self-heating; Silicidation; Silicides; Voltage; Work functions
• DOI: 10.1109/LED.2010.2051134
• ISSN: 0741-3106

In this letter, we propose a new lateral double-diffused metal-oxide-semiconductor field-effect transistor (LDMOSFET) with dual-work-function-gate (DWG) structure fabricated by utilizing silicidation of poly-Si layer. The step-etched poly-Si layer in the source side of the gate was totally converted to Ni-rich silicide, which resulted in a higher work function. On the other hand, in the drain side, only the upper part of the nonetched poly-Si layer was silicided, and the remaining lower part of the poly-Si layer was considered to be a gate with a lower work function. The fabricated DWG-LDMOSFET demonstrated remarkable improvement in device performances, such as 16.7, 16.4, 3.3, and 6.4% improvement in saturation drain current, in field-effect mobility, in subthreshold slope, and in the on resistance, respectively, while keeping almost the same breakdown voltage of 26 V and exhibiting less self-heating effect compared with the conventional single-work-function-gate LDMOSFET.