Characterization of PVD aluminum nitride for heat spreading in RF IC's

Abstract

Physical-vapor-deposited aluminum nitride, developed for heat spreading in RF ICs, is characterized by fabricating and measuring several different types of test structures. Among other things, it is shown that the material is a good dielectric insulator and has suitably low mechanical stress and piezoelectric response. With layers as thick as 6 µm, the electrothermal instabilities in a silicon-on-glass bipolar process are drastically reduced.

Laser‐Tuned Surface Wettability Modification and Incorporation of Aluminum Nitride (AlN) Ceramics in Thermal Management Devices

“…[ 47 ] The electrically insulating but thermally conductive nature of AlN substrates is ideal for direct integration with electronics or for direct‐to‐chip cooling applications, without grounding or other means that electrically isolate the thermal management system from the electronics. [ 5,6,7 ] However, there has been no known incorporation of ceramics in VCs featuring wickless components. Here, we report the first VC system featuring a wettability‐engineered hydrolysis‐arrested AlN evaporator ( Figure ), using water as the working fluid.…”

“…[ 3 ] Furthermore, the compatibility of AlN with Silicon owing to similar coefficients of thermal expansion (CTE, ≈2.6 × 10 −6 °C −1 for Si, compared to 4.5 × 10 −6 °C −1 for AlN), may eliminate long‐term thermomechanical fatigue, [ 4 ] and has encouraged researchers to incorporate AlN in microelectronics packaging or in heat sinks/spreaders that can be used for direct cooling of chips. [ 5–8 ] Other non‐oxide ceramics viz., SiC, BN, etc. also have similar favorable properties .…”

Morphological features in aluminum nitride epilayers prepared by magnetron sputtering

“…The studies of AlN thin film could be divided into the investigations which emphasize chemical and physical properties (mechanical, electrical, magnetic) [6,9,17,21,22], analysis of the films structure [4,7,12,15,16,19,[23][24][25]32] and combined, showing the dependences of the properties on the films morphology [2,11,13,14,26,[33][34][35]. The structure of the thin films can utterly differ from the structure of bulk material and have different structural perfection.…”

“…It is characterized by interesting tribological [5] properties, high value of hardness and high thermal conductivity, moderate piezoelectricity, low dielectric and acoustic losses [6], high resistance to temperature and stability in corrosive medium [7], good heat dissipation [8], high dielectric constant, moderately high electromechanical coupling coefficient [9], low coefficient of thermal expansion [4], high elastic stiffness [2], non-toxicity [10], electrical reliability [11], light weight [12], high fusion temperature [13], high refractive index, transparence in visible light [14]. All these characteristics in combination with large optical band gap make AlN suitable for applications in high power and high frequency devices, surface acoustic wave filters, insulating [7], passivating, cladding layers [15] and optical devices (blue light emitting diodes, short wavelength lasers, ultraviolet light detectors [16], compact disks, laser diodes, phase shift lithography masks, AlN/GaN multilayer devices [17], for growth of GaN layers on Al 2 O 3 and on 6H-SiC, which are also of interest as perspective materials), electroluminescent applications over a wide wavelength range [18], acoustic-optic devices.…”

“…AlN thin films can be applied for metaloxide-semiconductor field-effect transistor [21], CMOS technologies, microelectromechnical and microoptomechanical systems fabrication [22,23], electronic packaging, waveguides, sensors [24], electro-acoustic applications (microactuators, filters, resonators, acoustic modulators, surface acoustic wave devices) [6,11,25]. There are a lot of methods for thin films fabrication, such as pulsed laser deposition, reactive molecular beam epitaxy, vacuum arc/cathodic arc deposition, DC/RF reactive sputtering, ion beam sputtering, metal-organic chemical vapor deposition etc.…”