ASCENT Theme 1(B) / ALD of crystalline AlN for heatspreaders and RF buffer layers


Location: webex

Presenter: Andrew Kummel (UCSD) 

Abstract: As transistor size continues to decrease, it becomes a significant challenge to remove the heat generated during the operation of microelectronic circuits.  The use of electrically conductive heat spreaders complicates 3D integration in VLSI CMOS or stack memory devices and induces parasitic losses in RF MMICs. Crystalline AlN has a thermal conductivity close to that of Cu and is a good electrical insulator making it an ideal heat spreader material, For AlN to have high thermal conductivity it must be crystalline with large grains and low-defect density,  The low-temperature(<400 oC) deposition of polycrystalline AlN films is demonstrated by atomic layer annealing (ALA) which is a variant of ALD that utilizes a third pulse of ions in addition to the usual metal and co-reactant pulses   In the present study of AlN ALA, two metal precursors(TMA and TDMAA) were compared using anhydrous N2H4 as a co-reactant and argonions with tuned energy for the third pulse. High-quality AlN films are deposited with large grain size and low C/O contamination which can then be used as a templating layer for further high-speed AlN film growth.   The deposition of high quality, stress controlled AlN films deposited by ALA are successfully used as templates for thicker heat spreading layers deposited via sputtering and polycrystalline sputtered AlN films with near-record thermal conductivities for sub-0.5 micron thick films.   

JUMP/ASCENT task 2776.058 - Novel Routes to ALD of Crystalline Materials at Low  

This meeting is only available to the JUMP research community, such as Principal Investigators, Postdoc researchers, Students, and Industry/Government liaisons