Process for producing semiconductor device

Claim 2

A process for the production of a semiconductor device, comprising a step of performing a heat treatment at a temperature of from 950° C. to 1,250° C. for a period of from one to four hours on a silicon crystal having an impurity carbon concentration exceeding 1.0 ppm and not exceeding the solid solution limit to thereby form a denuded zone therein, a step of performing a heat treatment at a temperature of from 350° C. to 600 ° C. for a period of one to 24 hours on said silicon crystal having said denuded zone formed therein to thereby form a complex defect of impurity oxygen and impurity carbon therein, and a step of performing a heat treatment on said silicon crystal having said complex defect formed therein by the elevation of the temperature of said silicon crystal at a temperature increasing rate such that no core effect is broken to a level of from 900° C. to 1,250° C. to thereby effect an intrinsic gettering.

Claim 3

A process according to claim 1, wherein the temperature increasing rate is from 0.2° to 3.0° C./min.

Claim 4

A process according to claim 1, wherein the set of the step of performing a heat treatment at a temperature of from 350° C. to 600° C. for a period of one to 24 hours on said silicon crystal and the step of performing a heat treatment on said silicon crystal by the elevation of the temperature of said silicon crystal at a temperature increasing rate such that no core defect is dissociated to a level of from 900° C. to 1,250° C. is repeated a plurality of times.

Claim 5

A process according to claim 3, wherein the temperature increasing range is from 0.2° to 3.0° C./min.

Claim 6

A process for the production of a semiconductor device by an intrinsic gettering heat treatment of a silicon crystal, comprising analyzing a silicon crystal to thereby determine the concentration of impurity oxygen [Oi] and the concentration of impurity carbon [Cs] contained therein, calculating the expression: ##EQU2## wherein A stands for the coefficient for determining the temperature of a heat treatment to be performed on said silicon crystal, providing that the numerical value of said coefficient is expressed by the denomination of 1/ppm and [CO] stands for the desired concentration of a C--O complex generated within said silicon crystal in consequence of said heat treatment to thereby find the coefficient A for determining the temperature of the heat treatment, calculating the expression, 1,000/(T+273)=log 10 A+3.9, wherein T stands for the temperature (°C.) of the heat treatment to be performed on said silicon crystal to thereby find the temperature T for the heat treatment to be performed on said silicon crystal, performing a heat treatment at said temperature T for a period not exceeding four hours on said silicon crystal to adjust the concentration of a C--O complex defect contained in said silicon crystal, and thereafter, performing a heat treatment for a precipitation of oxygen.

Claim 7

A process for the production of a semiconductor device by an intrinsic gettering heat treatment of a silicon crystal, comprising analyzing a silicon crystal to thereby determine the concentration of impurity oxygen [Oi] and the concentration of impurity carbon [Cs] contained therein, calculating the expression: ##EQU2## wherein A stands for the coefficient for determining the temperature of a heat treatment to be performed on said silicon crystal, providing that the numerical value of said coefficient is expressed by the denomination of 1/ppm and [CO] stands for the desired concentration of a C--O complex generated within said silicon crystal in consequence of said heat treatment to thereby find the coefficient A for determining the temperature of the heat treatment, calculating the expression, 1,000/(T+273)=log 10 A+3.9, wherein T stands for the temperature (°C.) of the heat treatment to be performed on said silicon crystal to thereby find the temperature T for the heat treatment to be performed on said silicon crystal, performing a heat treatment at said temperature T for a period not exceeding four hours on said silicon crystal to adjust the concentration of a C--O complex defect contained in said silicon crystal, and thereafter, performing a heat treatment for a precipitation of oxygen.

Claim 8

A process according to claim 5, wherein the C--O complex defect is perceived and quantitatively analyzed by a method of low-temperature infrared absorption.

Claim 9

A process according to claim 5, wherein a concentration of the C--O complex defect is determined from an integrated intensity of a C--O infrared absorption peak at a wavelength of 1,104 cm -1 .

Claim 10

A process according to claim 5, wherein the time, t, required for the step of heat treatment performed at the temperature T to adjust the concentrations of said C--O complex defect is decided by calculating the expression, t=B{1-exp(-C/T)}, wherein B and C stand for constants for giving 0.3 hour and four hours as the time t respectively for 1,000° C. and 500° C. as the temperature T.