Whether supernovae (SNe) are a significant source of dust has been a<br />
long-standing debate. Abundant dust observed in high-redshift galaxies<br />
raises the fundamental astrophysical question of the origin of dust in<br />
Universe. AGB stars are too old to have evolved in early Universe. In<br />
contrast, SNe can occur within millions of years of the first<br />
generation of stars. I present dust formation observed in<br />
young supernova remnants (YSNRs) with Spitzer. Cas A and G54.1+0.3 YSNRs<br />
show unique dust features peaking at 21-micron, and E0102 and N132D<br />
show 18-micron dust features. In Cas A, we identify three distinct<br />
ejecta dust populations based on their continuum shapes including<br />
line-free map of 21 micron-peak dust closely resembles the Ar, O and<br />
Ne ejecta-line maps implying that dust is freshly formed in the ejecta.<br />
Spectral fitting of dust continuum shows amorphous dust and unique<br />
SN-produced dust compositions. We report detection of CO first overtone<br />
and fundamental bands from Cas A, indicating continuation of<br />
astrochmical processes since the explosion. I discuss compositions and<br />
masses of dust and association with ejecta and finally, dust<br />
contribution from SNe to early Universe.