  The RICOCHET reactor neutrino observatory is planned to be installed at
Institut Laue-Langevin starting in mid-2022. The scientific goal of the
RICOCHET collaboration is to perform a low-energy and percentage-precision
CENNS measurement in order to explore exotic physics scenarios beyond the
standard model. To that end, RICOCHET will host two cryogenic detector arrays :
the CryoCube (Ge target) and the Q-ARRAY (Zn target), both with unprecedented
sensitivity to O(10)eV nuclear recoils. The CryoCube will be composed of 27 Ge
crystals of 38g instrumented with NTD-Ge thermal sensor as well as aluminum
electrodes operated at 10mK in order to measure both the ionization and the
heat energies arising from a particle interaction. To be a competitive CENNS
detector, the CryoCube array is designed with the following specifications : a
low energy threshold ($\sim 50$eV), the ability to identify and reject with a
high efficiency the overwhelming electromagnetic backgrounds (gamma, betas,
X-rays) and a sufficient payload ($\sim 1$kg). After a brief introduction of
the future RICOCHET experiment and its CryoCube, the current works and first
performance results on the optimization of the heat channel and the electrode
designs will be presented. We conclude with a preliminary estimation of the
CryoCube sensitivity to the CENNS signal within RICOCHET.
