利用特殊接觸電極進行橫向擴散元件之特性分析與SPICE模型建立

Abstract

在此論文中，將觀察自發熱效應(self-heating effect)所引發的內部電壓(internal voltage)退化現象。我們提出一個具有特殊接觸電極之LDMOS(橫向兩次擴散之金氧半場效電晶體)結構，藉以量測高閘極脈波造成之內部電壓暫態變化。接著，我們將自發熱效應所造成之內部電壓退化與集極電流退化情形作一比較，最後證明內部電壓是觀察自發熱效應之較好方法。 我們將建立一個具有兩個組成元件之LDMOS SPICE模型，此模型也會納入自發熱效應的模擬。模擬結果準確描述了LDMOS在高閘極脈波下集極電流之暫態變化，顯示我們已成功建立了自發熱模型。在不同閘極和集極偏壓下，有/無自發熱效應之電流模擬結果，都將在論文中呈現。

Self-heating induced internal voltage degradation is observed. A novel lateral diffused MOS transistor with an additional metal contact for internal voltage measurement is introduced. An internal voltage transient at high gate voltage pulse is measured. A comparison of self-heating characterization by the internal voltage method and the conventional drain current method is presented. The internal voltage method is demonstrated to be more sensitive than drain current method for self-heating characterization. A two-component VI-based LDMOS SPICE model including self-heating effect is proposed. Our model accurately depicts the LDMOS drain current transient at high gate voltage pulse, demonstrating successful use of the self-heating model. Modeling results of the self-heating and non-self-heating currents at various VG and VD are also shown.