1. Technical Field
The present invention relates to a test apparatus and a test method.
2. Related Art
To test electrical characteristics of a semiconductor device, such as an insulated gate bipolar transistor (IGBT), a metal-oxide semiconductor field effect transistor (MOSFET), and a diode, by applying a current to the semiconductor device, the current is conventionally applied to the semiconductor device while the device under test is connected to a high-speed current source as disclosed in, for example, Japanese Patent Application Publication No. 2000-241503.
It, however, becomes more difficult to implement a high-speed current source as the value of the current increases. A conventional test apparatus uses a special power source that can respond at high speed and apply a large current, but such a special power source is expensive.
In addition, even such a special power source requires a certain period of time until the current reaches a sufficient test current level. Some currents may flow into the device under test before the current of the current source reaches a sufficient test current level, resulting in raising the temperature of the device under test. If the temperature of the device under test exceeds a test condition, the reliability of the measured values may be compromised. Thus, it is required to realize a low-cost test apparatus that can response at higher speed and can apply a large current to a device under test.