Fujitsu Corporation

Jeol Ltd.

Hiroshi Kaneta

Kunihiko Wada

Tsutomu Ogawa

Yoshimi Shirakawa

Haruhisa Mori

Tsunenori Yamauchi

Katsuto Tanahashi

Shuichi Muraishi

Katsuhiro Homma

A wafer processing method is provided that includes the steps of heating a silicon wafer containing oxygen and irradiating an infrared ray having a wavelength within a range of 7-25 &#x3bc;m on the silicon wafer, and controlling formation of oxygen precipitates within the silicon wafer by selectively setting a heating temperature for heating the silicon wafer and an irradiation intensity of the infrared ray.

Controlling oxygen precipitates in silicon wafers using infrared irradiation and heating

A semiconductor device comprises a silicon substrate of a resistivity above or equal to 800 &OHgr;&middot;cm and an oxygen concentration under or equal to 5&times;10 cm , and an inductor formed in the silicon substrate. A concentration of oxygen contained in the silicon substrate is set to be low, whereby the silicon substrate is less vulnerable to thermal donor effect, and even in a case that a silicon substrate of high resistivity is used, a semiconductor device which suppresses conversion of a conduction type of the silicon substrate while having an inductance of high Q. It is not necessary to bury a highly resistive layer in the silicon substrate, whereby a semiconductor device having an inductance of high Q can be fabricated by simple fabrication steps, which contributes to cost reduction of the semiconductor device.

Semiconductor device and method for fabricating the same

A semiconductor device is produced by a process for intrinsic gettering heat treatment of a silicon crystal in which the concentration of C--O complex defects destined to form seeds for oxygen precipitation in the silicon crystal is increased or an amount of oxygen precipitate in the silicon crystal is controlled, to thereby eliminate the dispersion of the amount from one crystal to another. In the heat treatment of the silicon crystal, the amount of oxygen precipitation can be controlled with a high accuracy.

Process for producing semiconductor device

A silicon crystal evaluation method includes the step of measuring, at room temperature, an intensity of an oxygen impurity infrared absorption peak of each of a plurality of silicon crystals at a wavenumber of 1107.+-.3cm.sup.-1, Each of the silicon crystals contains oxygen impurities, the silicon crystals including an evaluated silicon crystal having an unknown thermal history and reference silicon crystals having respective known thermal histories. The second step is to measure, at a temperature equal to or lower than 10K, an intensity of an oxygen impurity infrared absorption peak of each of the silicon crystals at a predetermined wavenumber. A third step is to calculate a first peak intensity ratio between the intensity of the oxygen impurity infrared absorption peak of each of the silicon crystals at 1107.+-.cm.sup.-1 and the intensity of the oxygen impurity infrared absorption peak at the predetermined wavenumber. The fourth step is to calculate a first difference between the first peak intensity ratio of the evaluated silicon crystal and a corresponding, second peak intensity ratio obtained when all oxygen impurities are isolated point lattice defects. The fifth step is to calculate a second difference between the first peak intensity ratio of each of the reference silicon crystals and the second peak intensity ratio. The sixth step is to evaluate the unknown thermal history of the evaluated silicon crystal from reference data which defines a relationship between the second difference and the known thermal histories.

Silicon crystal oxygen evaluation method using fourier transform

A method for measuring lattice defects in semiconductor such as a silicon crystal, detects an ultrasonic velocity of an ultrasonic pulse propagating through the semiconductor to which heat is variably applied. An elastic constant of the semiconductor is calculated from the ultrasonic velocity, and a concentration or density of lattice defects of the semiconductor is obtained by converting the elastic constant.

Growing community of inventors

Kawasaki, Japan

Hiroshi Kaneta