| 摘要 |
A radio frequency (RF) laterally diffused metal oxide semiconductor (LDMOS) device is disclosed which additionally includes a lightly-doped P-type buried layer under a P-type channel region and a moderately-dope P-type buried layer in the lightly-doped P-type buried layer. The two buried layers result in a lower base resistance for an equivalent parasitic NPN transistor, thereby impeding the occurrence of snapback in the device. Additionally, an equivalent reverse-biased diode formed between the channel region and the buried layers is capable of clamping the drain-source voltage of the device and sinking redundant currents to a substrate thereof. Furthermore, the design of a gate oxide layer of the RF LDMOS device to have a greater thickness at a proximal end to a drain region can help to reduce the hot-carrier effect, and having a smaller thickness at a proximal end to the source region can improve the transconductance of the RF LDMOS device. |
