Abstract A novel technique to detect oxydonor generation in semiconductor wafers. Oxydonor generation in a P-type substrate may be sufficient to create a P-N junction within the substrate which may adversely affect device performance. A technique of the present invention is a two-step process for determining the presence of such an oxydonor generated P-N junction. For a capacitor device, the capacitance of the device is measured under varying test voltages to determine a capacitance-voltage response. Then a second capacitance-voltage response is measured when the device is subjected to an external energy source. For a diode device, the forward current is measured with the device under varying test voltages to determine a current-voltage response. Then a second currrent-voltage response is measured when the device is subjected to an external energy source. By comparing device response with and without the application of external energy, a device having oxydonor generation problems is efficiently detected.
A method for nondestructive detection of oxydonor generation in a semiconductor diode device which includes a gate, a P-type silicon substrate having a N + region disposed therein, such that said N + region is disposed between a P-region of said substrate and said gate to form a P-N + diode, and wherein presence of oxydonors causes a further P-N junction to be formed in said substrate, comprising the steps of: placing a forward biased voltage potential across said diode device; measuring a forward current value of said diode device; subjecting said device to an external source of energy; measuring again said forward current of said diode device; comparing measurement of said forward current without said external source energy to measurement of said forward current with said external source of energy; wherein oxydonor generation is detected to be present in said substrate, if said forward current values are substantially different with and without said external source of energy.
Claim 2
Independent Claim
158 words
A method for nondestructive detection of oxydonor generation in a semiconductor diode device which includes a gate, a P-type silicon substrate having a N + region disposed therein, such that said N + region is disposed between a P-region of said substrate and said gate to form a P-N + diode, and wherein presence of oxydonors causes a further P-N junction to be formed in said substrate, comprising the steps of: placing a forward biased voltage potential across said diode device; measuring a forward current value of said diode device; subjecting said device to an external source of energy; measuring again said forward current of said diode device; comparing measurement of said forward current without said external source energy to measurement of said forward current with said external source of energy; wherein oxydonor generation is detected to be present in said substrate, if said forward current values are substantially different with and without said external source of energy.
Claim 3
Dependent Claim
16 words
The method of claim 1, wherein said voltage is varied across a negative range of values.
Claim 4
Dependent Claim
13 words
The method of claim 2, wherein said external source of energy is light.
Claim 5
Dependent Claim
13 words
The method of claim 2, wherein said external source of energy is heat.
Claim 6
Dependent Claim
41 words
The method of claim 2, wherein said forward current displays a P-N diode characteristic without said external source of energy, but displays a N + -P-N transistor characteristic when subjected to said external source of energy when oxydonor generation is present.