Abnormal Two-Stage Degradation Under Hot Carrier Injection With Lateral Double-Diffused MOS With 0.13-μm Bipolar-CMOS-DMOS Technology
Wei‐Chun Hung, Yu‐Fa Tu, Ting‐Chang Chang, Mao‐Chou Tai, Kuan-Hsu Chen, Fu‐Yuan Jin, Chien-Hung Yeh, Wei‐Chieh Hung, Chin-Han Chang, Hung-Ming Kuo, Chenhsin Lien
Abstract
In this work, the issue of abnormal two-stage hot carrier injection (HCI) degradation in n-type lateral double-diffused MOS (LDMOS) transistors is explored. The degradation mechanism is divided into two stages. The first stage is the electron injection into the interface layer (IL) caused by the impact ionization that occurs under the contact field plate (CFP), resulting in the degradation of the ON-current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {on}}{)}$ </tex-math></inline-formula> . The second stage of deterioration is the positive bias temperature instability (PBTI) effects caused by Joule heating, which leads to defects in the SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Si interface, and injects electrons in the channel into SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , which increases the subthreshold swing (S.S) of the device and causes the threshold voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {th}}{)}$ </tex-math></inline-formula> to shift. It has been proved by temperature variation experiments and technology computer-aided design (TCAD) simulations that HCI will indeed produce severe PBTI effects and lead to device degradation during long-term HCI.