Standard Test Method for Measuring Nonequilibrium Transient Photocurrents in p-n Junctions
|Publication Date:||15 May 1991|
1.1 This test method covers the measurement of photocurrents generated by radiation sources that provide pulses shorter than the time required for the device being tested to achieve equilibrium.
1.2 The lower limit of nonequilibrium photocurrent measurement possible is dependent upon the device type under test, the noise inherent in the test circuitry and apparatus, and the sensitivity of the measurement circuit. Usual measurable minimum photocurrent values range from 20 to 100 µA when the test circuit is terminated in 50 ω. The dose rate corresponding to signals of this magnitude is about 105 Gy(Si)/s. Above 5 × 108 Gy(Si)/s, special precautions are necessary in both measurement technique and data interpretation.
1.3 A nonequilibrium photocurrent characterization is primarily empirical. Interpretation of the photocurrent pulse is almost unique to the device type under test and the conditions under which it is tested.
1.4 Use of this test method is restricted to tests using as an ionizing pulse source either a flash X ray in the bremsstrahlung mode using peak energy of 2.3-MeV or greater or an electron linear accelerator (linac) with electron beam energy of 10 MeV or greater.
1.5 This test method is also applicable to measurement of equilibrium photocurrent of very fast-response devices see Method F 448
1.6 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.7 This standard does not purport to address the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.