Junction field effect transistor structure

A junction field effect transistor structure, having a substrate connecting end, comprising:

• a substrate of a first conductivity type;
• a source electrode comprising a heavy-implanted well layer of a second conductivity type, a well layer of said second conductivity type provided within said heavy-implanted well layer of said second conductivity type, and an implanted layer of said second conductivity type provided on said well layer of said second conductivity type;
• a drain electrode having a same structure with said source electrode;
• a grid electrode comprising a first implanted layer of said first conductivity type provided within said heavy-implanted well layer of said second conductivity type, and a polysilicon layer provided above said first implanted layer of said first conductivity type;
• a buried layer of said first conductivity type provided on said substrate;
• a heavy-implanted well layer of said first conductivity type provided on said buried layer;
• a well layer of said first conductivity type provided within said heavy-implanted well layer of said first conductivity type;
• and
• a second implanted layer of said first conductivity type provided on said well layer of said first conductivity type,
• wherein the substrate connecting end is connected with said substrate by said buried layer of said first conductivity type, said heavy-implanted well layer of said first conductivity type, said well layer of said first conductivity type and said second implanted layer of said first conductivity type.