SU673939A1 - Arrangement for measuring back currents of semiconductor devices - Google Patents

Description

(54) DEVICE FOR MEASUREMENT OF REVERSE CURRENTS OF SEMICONDUCTOR DEVICES

the total capacity of the pn-junction of the test device and the contact device for its connection. At low reverse currents of the device under test, the total capacitance is slowly charged until the voltage is set, which reduces the control performance and can lead to errors in measurements in the mass production of semiconductor devices.

The aim of the invention is to reduce the measurement time.

This is achieved by introducing a key element, an additional resistor and a gating circuit into the device for measuring the reverse currents of semiconductor devices, the key element and the additional resistor being sequentially included in the additional negative feedback circuit of the operational amplifier, and the gating circuit is connected between the output of the synchronization circuit and control input of the key element.

FIG. 1 is a block diagram of the device; in fig. 2 gives time diagrams for his work.

The device contains a pulsed-mode voltage source 1, a contact device 2 for connecting the device under test, an operational amplifier 3, covered by two parallel negative feedback circuits. Resistor 4 is permanently connected in one circuit and resistor 5 and key element 6 connected in series in an additional one. The device also contains a voltage meter 7 connected to the output of an operational amplifier, a synchronization circuit 8 designed to control the operation of a mode source 1, a voltage meter 7 and a gating circuit 9, which controls the key element 6.

When the device is operated, after connecting the tested semiconductor device to the contact device 2, a synchronization circuit 8 is included, which generates a control signal for starting the mode source 1, the voltage meter 7 and the gating circuit 9. The mode source produces a reverse voltage pulse from time tj applied to the tested semiconductor device, the amplitude of which corresponds to the specified measurement mode of the reverse current (Fig. 2 a). Until time tj, the key element 6 is open and the total capacitance of the pn junction of the test instrument and contact device 2 is quickly charged through the open key element and resistor 5, the resistance value of which is much less than the resistance of resistor 4 (Fig. 2b). At time tjj. The gating circuit 9 generates a control pulse of duration from ti to t, which covers the key element 6. At the output of the operational amplifier 3, a voltage is set (Fig. 2c) proportional to the reverse current of the controlled pn-junction, which is determined by the meter 7. At the time point C, the key element 6 is again opened and through it the discharge of the total capacitance is performed.

This device is more efficient than the known ones, as it allows to reduce the measurement time of reverse currents of semiconductor devices by at least 4 times. This allows it to be used in high-speed automated measurement systems.

Claims (3)

1. Semiconductor diodes. Parameters, measurement methods. Ed. I.I. Goryunova, Yu. R. Nosov, M., “Owls. Radio, 1968, p. 33. 2. Graham. Measurement of parameters of transistors using circuits on operational amplifiers. “Electronics, t. 45, No. 5, 1972. p. 45-52. 3.Onstee Rabb Martin. Semiconductor leakage testers grow up “edn, 1969, v. 14, No. 21, p. 39-42.