HIGH BREAKDOWN STRENGTH ELEMENT HAVING CHANNEL REGION AND STRAY REGION ISOLATED THROUGH INSULATOR AND MANUFACTURE THEREOF

PROBLEM TO BE SOLVED: To minimize a junction leakage current by electrically isolating a channel region and a stray region using an insulator wall and to enhance the reliability of an element by suppressing the generation of an abnormal current due to impact ionization. SOLUTION: A wall of silicon dioxide electric insulator 44 is formed between a channel region 41 and a stray region 42. Since a part 41a for forming a p-n junction is not present on surfaces other than the surface of the channel region 41 and the stray region 42, leakage current is minimized and ionization through initial collision is prevented. Furthermore, a passage of current flowing into a source 47 is blocked by the insulator 44, and generation of ions due to secondary collisions in the stray region 42 and increase of abnormal current can be suppressed. According to the structure, operational reliability of an element can be enhanced.