Method and apparatus for detecting surface ions on silicon diodes and transistors

Claim 1

An apparatus for detecting surface ions on P-N planar junction devices comprising: a. temperature control chamber means for housing said junction device and for maintaining the ambient temperature of said junction device at a selected discrete temperature in the range of -25* to -75* C., said temperature control means being adaptable to adjust and maintain the ambient temperature of said junction device at different discrete temperatures in said range; b. means for applying and varying reverse bias voltages in the range of 0 to 100 volts d.c. to the junction device while said device is maintained at a discrete temperature; c. current sensing means electrically connected to the junction device for quantitatively indicating current flowing through said junction device; and d. means electrically connected to said bias voltage means and to said current sensing means for plotting a current-versusvoltage characteristic curve of the junction device for increasing and decreasing bias voltage while said device is maintained at each said discrete temperature whereby currentversus-voltage characteristic curves indicating hysteresis are obtainable.

Claim 2

An apparatus for detecting surface ions on P-N planar junction devices comprising: a. temperature control chamber means for housing said junction device and for maintaining the ambient temperature of said junction device at a selected discrete temperature in the range of -25* to -75* C., said temperature control means being adaptable to adjust and maintain the ambient temperature of said junction device at different discrete temperatures in said range; b. means for applying and varying reverse bias voltages in the range of 0 to 100 volts d.c. to the junction device while said device is maintained at a discrete temperature; c. current sensing means electrically connected to the junction device for quantitatively indicating current flowing through said junction device; and d. means electrically connected to said bias voltage means and to said current sensing means for plotting a current-versusvoltage characteristic curve of the junction device for increasing and decreasing bias voltage while said device is maintained at each said discrete temperature whereby currentversus-voltage characteristic curves indicating hysteresis are obtainable.

Claim 3

A method for detecting surface ions on P-N junction planar devices comprising the steps of: a. maintaining said junction device at a selected discrete temperature in the approximate range of -25* to -75* C.; b. applying a reverse bias voltage to said junction device; c. varying said bias voltage over the approximate range of 0 to 100 volts d.c. in both increasing and decreasing directions to thereby obtain a hysteresis curve; d. plotting a current-versus-voltage characteristic hysteresis curve for each discrete temperature selected; and e. examining the characteristic hysteresis curves of the junction device to detect differences in the hysteresis effects demonstrated therein as indicating the presence of surface ions.

Claim 4

A method for detecting surface ions on P-N junction planar devices comprising the steps of: a. maintaining said junction device at a selected discrete temperature in the approximate range of -25* to -75* C.; b. applying a reverse bias voltage to said junction device; c. varying said bias voltage over the approximate range of 0 to 100 volts d.c. in both increasing and decreasing directions to thereby obtain a hysteresis curve; d. plotting a current-versus-voltage characteristic hysteresis curve for each discrete temperature selected; and e. examining the characteristic hysteresis curves of the junction device to detect differences in the hysteresis effects demonstrated therein as indicating the presence of surface ions.

Claim 6

A method for detecting surface ions on a P-N junction planar device comprising the steps of: a. maintaining said junction device at a selected discrete temperature in the approximate temperature range of -25* to -75* C.; b. applying a reverse bias d.c. voltage to said junction device; c. ploTting a reverse bias, current-versus-voltage characteristic curve of the junction device at said discrete temperature while varying said reverse bias voltage within an approximate range of 0 to 100 volts d.c. in a manner whereby a current-versus-voltage characteristic curve indicating hysteresis is obtainable; d. repeating each of the steps above for different discrete temperatures of said junction device within said temperature range to thereby obtain a family of current-versus-voltage characteristic curves; and e. detecting a counter-clockwise hysteresis effect in said curves or detecting an increase in bias voltage for a lower one of said discrete temperatures in order to maintain a constant leakage current as being indicative of the presence of surface ions on said junction device.

Claim 7

A method for detecting surface ions on a P-N junction planar device comprising the steps of: a. maintaining said junction device at a selected discrete temperature in the approximate temperature range of -25* to -75* C.; b. applying a reverse bias d.c. voltage to said junction device; c. ploTting a reverse bias, current-versus-voltage characteristic curve of the junction device at said discrete temperature while varying said reverse bias voltage within an approximate range of 0 to 100 volts d.c. in a manner whereby a current-versus-voltage characteristic curve indicating hysteresis is obtainable; d. repeating each of the steps above for different discrete temperatures of said junction device within said temperature range to thereby obtain a family of current-versus-voltage characteristic curves; and e. detecting a counter-clockwise hysteresis effect in said curves or detecting an increase in bias voltage for a lower one of said discrete temperatures in order to maintain a constant leakage current as being indicative of the presence of surface ions on said junction device.