Development of Large‐Diameter and Very High Purity Ge Crystal Growth Technology for Devices

High-purity germanium (HPGe) single crystals find their applications as radiation detectors especially for spectroscopy of high-energy photons and particles in nuclear physics. Growing “detector-grade” HPGe crystals, with tailored structural defects controlled impurity content, uniform throughout the crystal is a challenging task this type crystalline semiconductor material. All different process steps HPGe, namely, i) reducing dioxide powder into Ge metal; ii) zone refining intrinsic source material (6 N) up to an ultrahigh purity (13 N); iii) Czochralski growth high-purity are developed house. A specific preparatory coating entrenched part work. Gallium, dominant usually found can be avoided. Using these advanced know-hows, technology grow volume large diameter (3 in.) very high (net carrier concentration ≈ 5 × 1010 cm−3 or equivalent 1 per trillion level) successfully developed. The zone-refined bars show p-type conductivity. Some exhibit n-type conductivity, n–p p–n transition encountered experiment. Besides first results encompassing diameter, dislocation density (≈104 cm−2) realized.