Potential of 4H-SiC CMOS for High Temperature Applications Using Advanced Lateral p-MOSFETs

Abstract:

In this work, the impact of the n-well doping concentration on the channel mobility and threshold voltage of p-MOSFETs and their applications in CMOS-devices is evaluated. For this purpose lateral p-channel MOSFETs with different channel lengths (L = 800 μm, 10 μm, 5 μm, and 3 μm) and doping concentrations (N_D = 10¹⁵ cm^-3 and 8·10¹⁵ cm^-3) were fabricated and the respective field-effect mobility was extracted from the transfer-characteristics. Comparable to n-MOSFETs the mobility of p-MOSFETs was found to be the highest for the lowest doping concentration in the channel and the absolute value of the threshold voltage increases with increasing doping concentration [4]. To investigate its suitability for CMOS applications, inverters with different doping concentrations for n-MOSFET (N_A = 10¹⁵ cm^-3 and 10¹⁷ cm^-3) und p-MOSFET (N_D = 10¹⁵ cm^-3 and 8·10¹⁵ cm^-3) were built. For logic levels of 0 V and 10 V, the voltage transfer characteristic with the highest input ranges was obtained for a low p-MOSFET and a high n-MOSFET doping concentration. The lowest propagation delay time could be achieved with a low p-MOSFET and a low n-MOSFET doping concentration. At room temperature as well as at high temperatures T = 573 K the drain current of p-MOSFETs with channel lengths below 3 μm is hampered by the series resistance of the source and drain region which limits the performance of CMOS devices.

• Periodical: Materials Science Forum (Volume 858)
• Pages: 821-824
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.858.821
• Online since: May 2016
• Authors: Matthaeus Albrecht*, Tobias Erlbacher, Anton J. Bauer, Lothar Frey
• Keywords: 4H-SiC, CMOS, Field-Effect Mobility, High Temperature, p-MOSFET

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