초록 ▼

An LDMOS field effect transistor (80) provides protection against the inadvertent reversal of polarity of voltage applied across the device. To protect an N-channel device, a floating P-type blocking region (82) is provided surrounding the drain region (32). The blocking region (82) is spaced apart

An LDMOS field effect transistor (80) provides protection against the inadvertent reversal of polarity of voltage applied across the device. To protect an N-channel device, a floating P-type blocking region (82) is provided surrounding the drain region (32). The blocking region (82) is spaced apart from a body region (28) that forms the diffused channel (34) of the transistor (80). A first gate electrode (36) controls the conductivity of the diffused channel (34) and a second gate electrode (84) controls the conductivity of the surface (35) of the blocking region (82).

대표청구항 ▼

1. A method for protecting a field effect transistor 80 from an application thereto of a bias of reversed polarity, the field effect transistor 80 including a source region 30 and a drain region 32, each of first conductivity type and separated by a channel 34 of second conductivity type, the field

1. A method for protecting a field effect transistor 80 from an application thereto of a bias of reversed polarity, the field effect transistor 80 including a source region 30 and a drain region 32, each of first conductivity type and separated by a channel 34 of second conductivity type, the field effect transistor also including a first gate electrode and a body region 28 of the second conductivity type, the method comprising the steps of:interposing an additional region 82 of second conductivity type between the source region 30 and the drain region 32, wherein the additional region is electrically floating and wherein the additional region is spaced apart from the body region 28 and is part of the field effect transistor; and controlling current conduction across the additional region 82 by applying a potential to a second gate electrode 84 positioned overlying the additional region 82.