Effects of Growth Temperature on Carbon Nanotube Array Thermal Interfaces

Baratunde A. Cola, Birck Nanotechnology Center, School of Mechanical Engineering, Purdue University
Placidus B. Amama, Birck Nanotechnology Center, Purdue University
Xianfan Xu, Birck Nanotechnology Center, School of Materials Engineering, Purdue University
Timothy Fisher, Birck Nanotechnology Center, Purdue University

Abstract

Due to their excellent compliance and high thermal conductivity, dry carbon nanotube (CNT) array interfaces are promising candidates to address the thermal management needs of power dense microelectronic components and devices. However, typical CNT growth temperatures 800°C limit the substrates available for direct CNT synthesis. A microwave plasma chemical vapor deposition and a shielded growth technique were used to synthesize CNT arrays at various temperatures on silicon wafers. Measured growth surface temperatures ranged from 500°C to 800°C. The room-temperature thermal resistances of interfaces created by placing the CNT covered wafers in contact with silver foil (silicon-CNT-silver) were measured using a photoacoustic technique to range from approximately 7 mm2°C/W to 19 mm2°C/W at moderate pressures. Thermal resistances increased as CNT array growth temperature decreased primarily due to a reduction in the average diameter of CNTs in the arrays.