A high-quality thin gate oxide for application in Si/SiGe heterostructure PMOSFETs is prepared by nanometre silicon wet oxidation at 750 • C by taking full advantage of the peculiar phase in polysilicon thermal oxidation. The combination of low temperature and a short processing time prevents strain relaxation and Ge outdiffusion in the compressively strained SiGe channel. Its structural stability and interface quality are studied by x-ray double-crystal diffraction. Results of C-V characteristics and breakdown measurements indicate that the gate oxide exhibits a low fixed oxide charge density and a high dielectric breakdown field. Employing this gate oxide, Si/SiGe PMOSFETs with good output characteristics have been successfully fabricated.

Buck converter is widely used in the aerospace field. However, radiation in the aerospace environment will result in degradation or failure of devices and circuits. This paper presents a radiation-hard Buck, which is an adaptive on-time Buck. A radiation-hard adaptive on-time generator is proposed by utilizing of leakage current compensation. The proposed radiation-hard adaptive on-time generator is composed of an adaptive ontime timing block and a charging current generator. Finally, the proposed Buck is fabricated in a standard 0.18 µm BCD process. And the radiation tests show that the Buck still maintains stability after total ionizing dose irradiation at a total dose of 350 Krad (Si).