Direct laser writing/ultra-hyperdoping technology was harnessed to fabricate a universal CMOS-compatible Si-based broadband (UV-THz) n-p junction detector, with its spectral response controlled by external liquid helium-nitrogen cooling. Near-far IR (2–40 μm) temperature-dependent photoconductivity (PC) was revealed in a biased n-p junction, made of n-type sulfur-ultrahyperdoped Si (uh-Si, sulfur content ∼1 at. %) sub-micron-thick layer on a surface of a p-doped Si substrate. The observed broadband photoconductivity is provided by a dense quasi-continuum series of sulfur-impurity donor states near the conduction band bottom (so-called “intermediate band”, the bandwidth ≈0.6 eV), corresponding to IR-absorbing neutral and singly-ionized substitutional atomic and cluster centers of sulfur. The “intermediate” donor band supports the gradual “blue” spectral migration of PC maximum due to thermal ionization of deeper states at the temperature increasing in the range of 5–250 K. As a result, in the temperature range of 77–300 K complementary THz (wavenumbers <100 cm−1) spectroscopy indicates the predominating Drude-like conduction-band response of electrons and their gradually raising density ∼1019–1020 cm−3. Illustrating the thermal-ionization depletion of the donor sulfur states from the THz-probed plasma side, this unveils the unprecedently high concentration of electrically-active donor sulfur centers ∼1020 cm−3 and related donor-state density ∼1020 states/eV·cm3 in the uh-Si sample. Overall, these advances enable in situ laser writing of universal liquid helium/nitrogen cooled Si nano/micro/macrodetectors with broad – near-far IR and even THz – spectral response, crucial for photovoltaics, thermal and bio-imaging.