Inherent selective pulsed chemical vapor deposition of aluminum oxide in nm scale

Inherent selective pulsed chemical vapor deposition (CVD) of aluminum oxide on Si and SiO2 in preference to SiCOH has been studied. SiCOH is alkyl (-CxHy) terminated SiO2, which was used as a non-reactive surface. For aluminum oxide deposition, pulsed CVD processes using aluminum tri sec-butoxide (ATSB) and trimethylalu-minum (TMA) were tested. ATSB alone can induce a pulsed thermal CVD reaction to selectively deposit aluminum oxide at 300 degrees C sample temperature;-4 nm of aluminum oxide were selectively deposited on Si and SiO2 in preference to SiCOH. By adding a periodical pulse of TMA during ATSB pulses, higher selectivity was achieved with-12 nm and-14 nm of aluminum oxide on Si and SiO2 with around 0.4-0.5 nm root mean square (RMS) roughness at 330 degrees C. The high selectivity persisted on the nanoscale: STEM showed that-10 nm of aluminum oxide could be selectively deposited on nanoscale patterned features. The selectively deposited AlOx films showed low k (-4) dielectric performance with low leakage (around 10-6 A/cm2 at +/- 2 V for a 15 nm thick film). This selective aluminum oxide pulsed CVD process has the potential to be applicable in nanoscale fabri-cation, such as low k spacer and etch stop layer.

Automated summary

In this study, the inherent selective pulsed chemical vapor deposition (CVD) of aluminum oxide on Si and SiO2 was investigated, with preference to SiCOH. Two different reagents, aluminum tri sec-butoxide (ATSB) and trimethylaluminum (TMA), were tested for pulsed CVD processes. The results showed that using ATSB alone could selectively deposit aluminum oxide at a sample temperature of 300 degrees C, with a thickness of about 4 nm on Si and SiO2. By adding pulses of TMA during ATSB pulses, higher selectivity was achieved with a thickness of about 12 nm and 14 nm on Si and SiO2 at 330 degrees C.