  NeXT (New X-ray Telescope) is the next Japanese X-ray astronomical satellite
mission after the Suzaku satellite. NeXT aims to perform wide band imaging
spectroscopy. Due to the successful development of a multilayer coated mirror,
called a supermirror, NeXT can focus X-rays in the energy range from 0.1 keV up
to 80 keV. To cover this wide energy range, we are in the process of developing
a hybrid X-ray camera, Wideband X-ray Imager (WXI) as a focal plane detector of
the supermirror. The WXI consists of X-ray CCDs (SXI) and CdTe pixelized
detectors (HXI), which cover the lower and higher X-ray energy bands of 0.1-80
keV, respectively. The X-ray CCDs of the SXI are stacked above the CdTe
pixelized detectors of the HXI. The X-ray CCDs of the SXI detect soft X-rays
below $\sim$ 10 keV and allow hard X-rays pass into the CdTe detectors of the
HXI without loss. Thus, we have been developing a "back-supportless CCD" with a
thick depletion layer, a thinned silicon wafer, and a back-supportless
structure. In this paper, we report the development and performances of an
evaluation model of CCD for the SXI, "CCD-NeXT1". We successfully fabricated
two types of CCD-NeXT1, unthinned CCDs with 625-um thick wafer and 150-um thick
thinned CCDs. By omitting the polishing process when making the thinned CCDs,
we confirmed that the polishing process does not impact the X-ray performance.
In addition, we did not find significant differences in the X-ray performance
between the two types of CCDs. The energy resolution and readout noise are
$\sim$ 140 eV (FWHM) at 5.9 keV and $\sim$5 electrons (RMS), respectively. The
estimated thickness of the depletion layer is $\sim$80 um. The performances
almost satisfy the requirements of the baseline plan of the SXI.
