MnSi crystals with chemically induced negative pressure (doped by less than 1% Ge) have been synthesized by the Czochralski method. X-ray powder diffraction has revealed that the samples are crystallized in the B20 structure, inherent to pure MnSi, without any impurity phases. The lattice constant a is slightly larger than that of undoped MnSi. The samples have a spiral spin structure with the wave vector | k | = 0.385 nm − 1 at low temperatures. The ordering temperature is enhanced up to T C = 39 K. The critical field H C2 shows an increase of about 25% for the doped samples. Close to the critical temperature the A phase occurs. The temperature range of the A phase in the (H-T ) phase diagram for the doped compound ranges from T A = 27.5 K, characteristic for pure MnSi, to T C = 39 K in the zero-field cooled (ZFC) regime of magnetization. The magnetic features of the (H-T ) phase diagram of the compounds MnSi are reminiscent of those observed for the MnSi thin films on the Si substrate.