Silicon Carbide Thin Films using 1,3-Disilabutane Single Precursor for MEMS Applications - A Review

Abstract

Significant progress has been made over the past several years in the development of silicon carbide (SiC) films grown via low pressure chemical vapor deposition (LPCVD) from the single precursor, 1,3-disilabutane (DSB) for microelectromechanical systems (MEMS) applications. Polycrystalline 3C-SiC (poly-SiC) deposition capabilities have been scaled up from depositions on a single 1cm × 1cm piece of Si to forty-five 150 mm Si wafers. Insitu doping with gaseous ammonia and post-deposition annealing have been developed, resulting in a lowest resistivity of ~0.02 Ω·cm to date. Plasma etch chemistries for SiC with good selectivity to silicon dioxide and silicon nitride masking layers have been discovered and characterized. Extensive mechanical, electrical, and tribological characterization of the SiC films have been performed. These SiC films have been applied as both MEMS structural layers for high-frequency resonators and thin film coating layers to improve anti-stiction properties and harsh environment performance.

Investigating routes toward atomic layer deposition of silicon carbide: Ab initio screening of potential silicon and carbon precursors

“…We find that unimolecular decomposition of most of these precursors is thermodynamically favorable at low temperature. Experimentally, growth of SiC by CVD using singlesource precursors was shown for 1,3-disilabutane (SiH 3 -CH 2 -SiH 2 -CH 3 ) (low pressure CVD, 750 C), 16 silacyclobutane [SiH 2 (CH 2 ) 3 ] (T ¼ 800-1200 C), 20 methylsilane (CH 3 -SiH 3 ) (T ¼ 800 C), 17 and MTS (T ¼ 1570 C). 32 Our calculations show that decomposition of 1,3-disilabutane, silacyclobutane, and methylsilane is thermodynamically favorable at T ¼ 1000 C with DG ¼ À3.5, À4.5, and À3.8 eV/SiC, respectively.…”

“…12 A review of chloride-based CVD growth of SiC was done by Pedersen et al 15 Singlesource precursors (containing both Si and C in the same molecule) have also been used for CVD of SiC. 16 These precursors include: MTS, methylsilane (CH 3 -SiH 3 ), 17 20 and 1,3-disilabutane (SiH 3 -CH 2 -SiH 2 -CH 3 ). 16 As was mentioned above, experimentalists are facing difficulties in growing SiC films by ALD or PEALD.…”

“…16 These precursors include: MTS, methylsilane (CH 3 -SiH 3 ), 17 20 and 1,3-disilabutane (SiH 3 -CH 2 -SiH 2 -CH 3 ). 16 As was mentioned above, experimentalists are facing difficulties in growing SiC films by ALD or PEALD. Theoretical modeling of ALD using density functional theory (DFT) provides a complementary view to the experimental techniques.…”